WEBVTT 1 00:00:09.900 --> 00:00:11.550 Alec: Okay, let's start. 2 00:00:12.660 --> 00:00:27.300 Alec: Good afternoon, everyone. It great gives me great pleasure to introduce the speaker for this very first Mitzi seminar of the of the season and also in the new online format. 3 00:00:28.380 --> 00:00:31.920 Alec: So our speaker today is Professor Jorge rocker 4 00:00:33.090 --> 00:00:41.550 Alec: Jorge is a university distinguished professor in the Department of electrical and computer engineering and physics, the Colorado State University. 5 00:00:42.150 --> 00:00:52.410 Alec: His research interests in the physics and development of compact x ray lasers and their applications, the development of high power lasers and the study of high power laser interactions with matter. 6 00:00:52.860 --> 00:00:55.830 Alec: In particular, with the goal of creating bright X resources. 7 00:00:56.490 --> 00:01:06.300 Alec: It's group is known for contributions to the development of bright table top software trailblazers including the demonstration of the first table tops off that career laser and our application in several fields. 8 00:01:06.690 --> 00:01:17.970 Alec: Gluten nanotechnology and nanoscience and diagnostics of dense plasmas as group has developed a multi hurts at repetition rates pet what class laser and kilowatts level average power hype. 9 00:01:18.450 --> 00:01:26.280 Alec: Pulse energy because I can solid state lasers recently his group show that intense laser irradiation have ordered nanostructures 10 00:01:26.790 --> 00:01:39.540 Alec: Creates an ultra high energy density plasma regime, leading to multi gigabit pressures and extreme degree of ionization and record conversion efficiency second x ray pulses and microsecond fusion. 11 00:01:41.400 --> 00:01:52.500 Alec: His results have been published in 270 peer reviewed journal articles he received the author el cholo prize and laser science from the American Physical Society. 12 00:01:52.830 --> 00:02:01.230 Alec: And the willacy lamb Award for laser at science and quantum optics. He was elected fellow of the American Physical Society. The Optical Society of America. 13 00:02:01.620 --> 00:02:21.720 Alec: And the Institute of Electrical and Electronic engineers, he received in IEEE Elliott Elliot is distinguished lecturer award and early in his career. He was a National Science Foundation presidential young investigator and although it's not on his biography recently he was also the 14 00:02:22.890 --> 00:02:40.170 Alec: Founding principal investigator of a new network of lasers called laser net, which I believe he will talk about, which is linking up mid-scale later facilities around the US and particularly grateful for his leadership. 15 00:02:40.680 --> 00:02:51.600 Alec: And that and so normally in these seminars, we would now go to awarding the speaker with the MIPS in Mark 16 00:02:52.230 --> 00:03:09.030 Alec: But of course we're under covert conditions, but even under these conditions, it has been arranged so an Mc, Mc, I believe, has been sent to Jorge. So if you could lift it up so that everyone can see, there we go. I just hold out for for a snapshot 17 00:03:10.890 --> 00:03:14.130 Julia Falkovitch-Khain: Would you please say something. So you take the screen and I 18 00:03:14.940 --> 00:03:22.920 Jorge Rocca: Yes, sure. Well, you know, I'm very thankful for the invitation. And then, thank you. Alex for the, you know, very generous introduction. 19 00:03:23.430 --> 00:03:36.480 Jorge Rocca: And in particular to, you know, a mark listener for the invitation. You know, I'm having a great time talking to a you know friends and colleagues and you know meeting students. So thank you. Thank you again. 20 00:03:38.190 --> 00:03:50.220 Alec: Thank you very much away. And so I'll pass over to him to speak in a second. But just first a quick note, you will have all been muted on entry to the chat room. So at the end when there's questions. 21 00:03:50.820 --> 00:04:00.630 Alec: Just to remind you to unmute yourselves before you ask your questions, obviously. And also, if you have any technical issues occurring, they should be reported in the 22 00:04:00.930 --> 00:04:17.730 Alec: chat window. And there are two moderators, who will be monitoring that throughout. So without further ado I positive to Jorge his talk will be on relativistic Nana photonics creating extreme plasma conditions and fields with ultrafast lasers. Thank you. 23 00:04:18.810 --> 00:04:23.130 Jorge Rocca: Well, thank you very much. Alex again. So I'm going to share the screen and 24 00:04:24.360 --> 00:04:25.290 Jorge Rocca: Okay, I think. 25 00:04:26.430 --> 00:04:31.140 Jorge Rocca: Let me see you have, you will have to tell me right if you can 26 00:04:32.220 --> 00:04:33.390 Jorge Rocca: If you can see it. Okay. 27 00:04:35.010 --> 00:04:37.770 Jorge Rocca: And you should be seen introduction slide right now. 28 00:04:38.010 --> 00:04:39.270 Alec: We do, we can see it. 29 00:04:39.660 --> 00:04:43.080 Jorge Rocca: Okay. Excellent. Well, let me again a 30 00:04:43.650 --> 00:04:46.290 Jorge Rocca: Thank thank you for the invitation. Right. 31 00:04:46.770 --> 00:04:49.560 Jorge Rocca: It is a pleasure to give this 32 00:04:51.150 --> 00:05:12.600 Jorge Rocca: Talk right on this very distinguished series right at the University of Michigan that has contributed so much right to lasers and generals through older fans lasers and to the plasma. So it is an honor to to be here. And so we see 33 00:05:13.740 --> 00:05:29.610 Jorge Rocca: I'm feeling very good. And so the a work. I will describe rights being conducted at Colorado State universities across the University is located in Fort Collins, Colorado. There is a the foothills. 34 00:05:30.480 --> 00:05:37.650 Jorge Rocca: Of the Rocky Mountains. As you can see here and basically this is actually downtown Fort Collins these buildings here. 35 00:05:38.130 --> 00:05:57.870 Jorge Rocca: Belong to the university university campuses, more or less here and our lab actually is at the very food hills is just a few miles away from from the main campus in what's called Foothill campus. And we have one of two of our largest LASER SYSTEMS into a new building a 36 00:05:59.070 --> 00:06:04.260 Jorge Rocca: Name called the advanced beam lab, the university bill for us. And just a few years. 37 00:06:04.620 --> 00:06:12.960 Jorge Rocca: Ago around four years ago and it's right or the foothills after that there is a damn one in. As you can see, what are them on the other side is a large reservoir. 38 00:06:13.260 --> 00:06:19.230 Jorge Rocca: From where you know if you are there, you can have a good view you know of town. And, you know, our lab. 39 00:06:20.010 --> 00:06:39.570 Jorge Rocca: As ALEC already mentioned right actually has something in common, right, with the University of Michigan in that a we both have, you know, a very intense. You know better what class lasers, right, University of Michigan Coco Chanel and Alec Thomas and 40 00:06:41.430 --> 00:06:50.430 Jorge Rocca: Lewis one day on colleagues right half. And this is basically a very powerful laser in which they have obtained right the 41 00:06:50.910 --> 00:07:02.760 Jorge Rocca: Pioneer and results during, you know, many years. We at CSU have a seminar laser and we are a fortunate that a about three years ago, the US Department of Energy. 42 00:07:03.180 --> 00:07:15.270 Jorge Rocca: Form a network of the most intense lasers in North America started being the most intense lives in the US, but more recently I Mrs in Montreal in Canada was added. 43 00:07:15.810 --> 00:07:34.260 Jorge Rocca: So this network provides meantime this very intensive laser facilities to users. So basically any researcher from any situation right can fly for being time there is an independent review process that 44 00:07:34.800 --> 00:07:40.620 Jorge Rocca: You know the facilities are not involved in. So it's blind to us right it's handled by department of energy. 45 00:07:41.760 --> 00:07:48.180 Jorge Rocca: Tommy man from Lawrence Livermore lab is the chair and that's all we know because the panel right for you know for the facilities. 46 00:07:48.570 --> 00:07:59.100 Jorge Rocca: Is blind to the facility. So it's a transparent process and location time we have just been renewed actually last month for a three additional ears. 47 00:07:59.580 --> 00:08:06.330 Jorge Rocca: To continue providing you know being time to to users. So this is a goodness to 48 00:08:07.140 --> 00:08:18.690 Jorge Rocca: The entire you know physics community, particularly the high energy density physics communion. And as I mentioned, both, you know, the University of Michigan and us our partner on this and 49 00:08:19.380 --> 00:08:32.700 Jorge Rocca: On the same network him. So going back to what we do in our lab and I could define we do in our lab divided between developing 50 00:08:33.210 --> 00:08:43.440 Jorge Rocca: A high power lasers and we tried to develop unique unique I powerless right and then using them to do applications which 51 00:08:44.250 --> 00:08:51.090 Jorge Rocca: May be either do other lasers with different characteristics like doing suffix racers that we have been involved with for many years. 52 00:08:51.570 --> 00:09:01.800 Jorge Rocca: Or to study for example relativistic like the laser matter interaction, right. So, just very shortly. A, for example, recently we demonstrated 53 00:09:02.370 --> 00:09:10.500 Jorge Rocca: A one. Jul Pico second laser operated at one kilohertz repetition. Right. So that's one kilowatt average power right 54 00:09:11.010 --> 00:09:21.750 Jorge Rocca: Which with some unique unique plasma studies come you know come be done. So these are very compact laser is basically occupying just one and a half, you know, an optical table. 55 00:09:22.380 --> 00:09:33.330 Jorge Rocca: And then we also are involved in developing much more intense lasers and we have developed is 0.8 d phi beta one laser that is the one that we offer. 56 00:09:33.930 --> 00:09:45.120 Jorge Rocca: For users and liaison that that it has a rather unique, you know, a capability of operating at 3.3 posts per second, up to, you know, high, high repetition. Right. 57 00:09:45.630 --> 00:09:52.320 Jorge Rocca: And this is the laser that we're using to struggle reduce the legs and matter interactions which is basically the subject right of 58 00:09:53.190 --> 00:09:58.890 Jorge Rocca: A today stock. So to them basically concentrating run on blessed to be there is a matter interactions. In fact, 59 00:09:59.250 --> 00:10:06.240 Jorge Rocca: Interaction or touch or pathways with nano structures using this laser about which I will say a few more words so 60 00:10:06.870 --> 00:10:19.200 Jorge Rocca: What's the motivation of this right there. Well, the motivation is to generate extreme plasma conditions and just to, you know, give a reference for example, right, be the center of the sun. Right. 61 00:10:19.650 --> 00:10:31.200 Jorge Rocca: Has a pressure of a 240 gigabytes right here on Earth, right in the more largest laser like the National Ignition Facility right have reached 62 00:10:32.400 --> 00:10:41.190 Jorge Rocca: Basically pressure of more than hundred 50 right gigabytes is a mega joules. So, so in one of the motivation of our research is to create these 63 00:10:41.670 --> 00:10:48.810 Jorge Rocca: Extreme plasma conditions, but with a compact laser. Like, for example, if the other angels right and 64 00:10:49.440 --> 00:10:57.540 Jorge Rocca: We have, for example, simulations that predict the interaction of an intense laser, the intensity 110 to 22 watts per 65 00:10:58.170 --> 00:11:08.400 Jorge Rocca: square centimeter with a align nanostructures could produce right if everything's done right and pressures in of the order of 300 66 00:11:08.880 --> 00:11:15.510 Jorge Rocca: Gigabytes so extreme three conditions. So how are we doing this. Well, this is our approach. 67 00:11:16.020 --> 00:11:26.910 Jorge Rocca: Normally right traditionally a mini laser in a matter interactions consists in irradiating right in target a solid material. 68 00:11:27.330 --> 00:11:37.320 Jorge Rocca: With a with a pause. So when the police arrived, the leading edge of the pause arrives into them into a target right release an intense pulse we nearly form a plasma. 69 00:11:38.220 --> 00:11:51.480 Jorge Rocca: And this plasma. A will form a critical density surface a that and we become basically a reflector for him. The remaining of the laser light that is impinging on them. 70 00:11:51.840 --> 00:11:58.500 Jorge Rocca: On the plasma. So it makes it hard to couple right the energy into the plasma plasma. Plasma that's created is a 71 00:11:59.040 --> 00:12:10.680 Jorge Rocca: rather thin right it's not, you know, the high volume high volume plasma and the density, as I was saying is a limited to the critical density that for an optical laser. They were one microwaves. Right. 72 00:12:11.130 --> 00:12:20.550 Jorge Rocca: Is a pro one micron laser beam 110 to 21 electrons per centimeter, which is still a couple of orders of magnitude below solid density 73 00:12:21.150 --> 00:12:40.740 Jorge Rocca: So the approach we have done to create near solid density plasmas with a temperatures of many killer electron volts consists not any radiating em, you know, Fred solid surface, but rather irradiating a structure a consistent of 74 00:12:41.580 --> 00:12:48.810 Jorge Rocca: Align a will align nano structure. Like, for example, align nanowires as you can see here right on this electron microscope. 75 00:12:49.500 --> 00:13:00.270 Jorge Rocca: Images and the idea is that if you come with a sufficiently short pause. Let's say for example 15 seconds or so different. The second the pause. We have the chance to penetrate deep 76 00:13:01.020 --> 00:13:16.920 Jorge Rocca: Into the material into the nano wire array A and a positive energy very efficiently right these nano structures are very highly absorbent. For example, this picture I have on the bottom left right of the screen. 77 00:13:17.490 --> 00:13:29.220 Jorge Rocca: Is a picture of an array of nickel nanowires when we all know how Nick, it looks like right very, very shiny metal right here is I'm am. I am sorry, I think. 78 00:13:30.690 --> 00:13:33.420 Jorge Rocca: Let me see. I lost this light here for 79 00:13:34.470 --> 00:13:35.700 Jorge Rocca: You see if I can go back 80 00:13:41.460 --> 00:13:42.420 Let me see. 81 00:13:46.320 --> 00:13:48.330 Jorge Rocca: Okay, so you can see the slide right 82 00:13:52.080 --> 00:13:53.340 Jorge Rocca: Hello. Can you see this line. 83 00:13:54.570 --> 00:13:55.680 Mark Kushner: Yes, we can see the slide. 84 00:13:55.980 --> 00:13:56.250 Jorge Rocca: Okay. 85 00:13:56.280 --> 00:13:58.260 Mark Kushner: Thank. Thank you so much. So 86 00:13:58.890 --> 00:14:05.790 Jorge Rocca: So. So as I was saying right this ultra short pause will penetrate a before the nanowires are heated 87 00:14:06.270 --> 00:14:13.380 Jorge Rocca: And a they explode right when they explode the plasmas will merge creating in a classroom, a genius plasma. 88 00:14:13.740 --> 00:14:26.310 Jorge Rocca: That because you started with the material that is a significant fraction of solid band. So, for example, 20% or 30% of sort of solid density, you end up with the plasma which 89 00:14:26.790 --> 00:14:37.260 Jorge Rocca: Is near solid density has a high volume, right, and a, a nice extremely hard and, for example, the electron density can be achieved. 90 00:14:37.620 --> 00:14:52.080 Jorge Rocca: Is hundreds of times, right, the critical density. So what ends up with this consider volume plasma with them in basically in orders of magnitude right in higher higher density. So him. 91 00:14:54.810 --> 00:14:58.080 Jorge Rocca: So a already several years ago we 92 00:14:59.100 --> 00:15:08.640 Jorge Rocca: Basically conducted simulations. These were conducted with a particular cell code developed by our colleague em Alexander, who have a university of Dusseldorf 93 00:15:09.120 --> 00:15:19.230 Jorge Rocca: That showed that with a 50 femtosecond 50 502nd boss of a mother's relative isn't that intensity of 510 to 15 watts per square centimeter 94 00:15:20.100 --> 00:15:33.150 Jorge Rocca: A an array of 55 millimeter diameter a nickel nanowires a 12% solid density would form a fairly deep volume large volume, which 95 00:15:33.870 --> 00:15:42.330 Jorge Rocca: Is the laser field will penetrate the passing very efficient in the positive energy here you see the computed a 96 00:15:42.870 --> 00:15:51.330 Jorge Rocca: Basically impinging energy and the amount reflector. So the great majority right is absorbed and on the process if they 97 00:15:52.110 --> 00:16:05.850 Jorge Rocca: They lie penetrate deeper into the wires and the wires are heated, they start exploding from the deep down and a basically after a few hundred femtoseconds. You end up with this question my genius plasma. 98 00:16:06.420 --> 00:16:15.210 Jorge Rocca: And would you see here on the bottom is a map of electron density on units of critical density in which blue here right is getting right to 100 99 00:16:16.230 --> 00:16:25.920 Jorge Rocca: Times right there, the critical density. The Wire themselves, right, a much denser. So to be able to do experiments and demonstrate this right we learn 100 00:16:26.520 --> 00:16:35.790 Jorge Rocca: From our chemistry, colleagues, a help to grow nanowire structures in our own lab because we need them right in large quantities we destroy them every time we should 101 00:16:36.390 --> 00:16:50.880 Jorge Rocca: Right, so you have here electron microscope pictures or, for example, an array of 55 nano meter in diameter, find micro long nanowires and then a larger diameter here hundred 50 you can see they're 102 00:16:51.240 --> 00:17:03.570 Jorge Rocca: Fairly orderly and we can do this in many materials. For example, we can do it on goal. This is an array of 400 and immediate goal nanowires we can change the density here on the bottom. 103 00:17:05.400 --> 00:17:19.830 Jorge Rocca: Row with you can see is a 15% solid density targets 30% right solid density target and we don't target in already several years ago we use laser pulses of only have a jewel of 104 00:17:21.000 --> 00:17:28.410 Jorge Rocca: Energy right 50 502nd duration to irradiated one of this a race of nickel nanowires 105 00:17:29.310 --> 00:17:45.570 Jorge Rocca: And a we did a x ray spectroscopy and time integrated. And what you see here is spectra is expected of these em McMullen aware plasma covering the region between 1.5 and 1.7 am strength. 106 00:17:46.350 --> 00:17:57.660 Jorge Rocca: And the tracing rep right is the spectrum for the nickel nanowire array, we can see that's dominated by lines of helium, like, Nicole. 107 00:17:58.200 --> 00:18:05.490 Jorge Rocca: So that is Nicole was stripped from all 28 electrons, except to write and 108 00:18:06.420 --> 00:18:13.770 Jorge Rocca: Minus striking thing to notice is that if one he radiates if flat targets a foil of nickel right with the same. Pause 109 00:18:14.130 --> 00:18:23.820 Jorge Rocca: This is the spectrum x ray spectrum that we obtain on this region of the spectrum that we see know Tommy Kalia and is atomic lines are all we only see the K alpha line. 110 00:18:24.750 --> 00:18:37.650 Jorge Rocca: And in fact, the spectrum, multiply by 10 right so you can see is a very high degree of ionization on the nano plasma plus a much larger right emission of X rays. In fact, like, like, like 100 x 111 00:18:38.370 --> 00:18:44.550 Jorge Rocca: Him now question is, and in fact the first time we presented this results, you know, some 112 00:18:45.450 --> 00:18:54.090 Jorge Rocca: Good questions were, well, how do you know that you are hitting a significant volume and not just a very thin layer, the top right so 113 00:18:55.080 --> 00:19:07.320 Jorge Rocca: To answer that question in a clear manner we learn how to him a build out the fire brigade nanowires have dual composition. So each wire now. 114 00:19:07.650 --> 00:19:18.630 Jorge Rocca: The bottom part of the wire would be a one material and the top part of another. And we use this combination nickel same material. I just show the previous spectra. 115 00:19:19.410 --> 00:19:27.840 Jorge Rocca: And cobalt simply because they are contiguous element right on the periodic table says that their characteristic lines will simultaneously appear 116 00:19:28.200 --> 00:19:36.960 Jorge Rocca: On the same frame of the X ray crystals. But Tom parameter. For example, here this spectrum of such an honor wire a combined and a wire. 117 00:19:37.530 --> 00:19:47.430 Jorge Rocca: You know array. And these lines correspond to him like and leave him like a nickel and those one correspond to helium like lithium cobalt right so the experiment them consistent 118 00:19:48.210 --> 00:19:55.140 Jorge Rocca: In having trouble on the bottom and fabricator race with different length of nickel on top. 119 00:19:55.650 --> 00:20:11.370 Jorge Rocca: And monitor the lines particular the cover lines to see how much lengths of nickel wire we can put on top and still see a mission from helium likable right on the bar indicating right we are creating an extremely hot plasma. 120 00:20:12.570 --> 00:20:18.420 Jorge Rocca: Buried a under, under, you know, significant amount of nickel on the top. And here are the results. 121 00:20:19.170 --> 00:20:31.200 Jorge Rocca: The results right indicated that we see helium like copper lines down to four to five microns that into the into the nano wire right so we are indeed. 122 00:20:31.920 --> 00:20:36.870 Jorge Rocca: Basically, causing a volumetric volumetric hearing and not just kidding right and 123 00:20:37.380 --> 00:20:46.650 Jorge Rocca: These experiments were conducted for them to 19 a higher intensity and the one I you know I already mentioned later. These were later you know later experiments now. 124 00:20:47.490 --> 00:20:57.360 Jorge Rocca: Question is, how fast does the boss need to be such the balls can penetrate deep into this array and efficiently the positive energy 125 00:20:57.750 --> 00:21:06.150 Jorge Rocca: Before the wires will explode and form a critical density surface right from with the remaining of the pause will be reflected 126 00:21:06.600 --> 00:21:18.540 Jorge Rocca: So to answer that question, we made an experiment in which we irradiated and unaware is not with one pause, but with a sequence of two passes. 127 00:21:19.050 --> 00:21:28.050 Jorge Rocca: Separated by a control delay delta t. Right. So the idea is if the paws are close to each other right they act pretty much like a 128 00:21:28.380 --> 00:21:38.820 Jorge Rocca: One single short pause and they will be able to penetrate deep into an unaware ray and the positive energy before the nanowire explode and you're back to forming, you know, in 129 00:21:39.240 --> 00:21:49.380 Jorge Rocca: Continuous a critical density surface and then start separating the policies to look for the moment, which does happen. So them a main indicator that when 130 00:21:50.310 --> 00:21:58.950 Jorge Rocca: A moderator to to decide and when, when this, you know, efficient copying starts occurring as we increase the 131 00:21:59.310 --> 00:22:05.340 Jorge Rocca: The length of the pulse of the separation between the bosses was to monitor the mission for a human for line right 132 00:22:05.790 --> 00:22:18.480 Jorge Rocca: And where we can see here is the 450 femtoseconds radio separation. The mission from him alpha is practically constant. And then after Hannah and 50 femtosecond properly drops right 133 00:22:19.080 --> 00:22:35.430 Jorge Rocca: And even an idea, basically, of how fast you need to deposit the energy for this mechanism right to, you know, to take place this word than an 18 and a meter nanowires at the neuron to represent right solid density at the intensities indicated here. 134 00:22:36.450 --> 00:22:49.560 Jorge Rocca: So simulation show right on that on this process and intensity just mentioned around 14 to 19 watts per square centimeter. They wires. Get em extremely hot right and a the 135 00:22:50.610 --> 00:22:55.530 Jorge Rocca: Energy density. The passing of the wires. So the orders 20 mega joules per cubic centimeter 136 00:22:56.160 --> 00:23:03.390 Jorge Rocca: And very high pressure local locally developed in the nano where explode forming this you know kwassa uniform plasma. 137 00:23:03.780 --> 00:23:17.610 Jorge Rocca: And even when they nanowires explode and fill the gaps between the wires. When an end up with the plasma in with the energy position is one gigabyte per cubic centimeter and pressures of gigabytes. So, this 138 00:23:18.990 --> 00:23:39.690 Jorge Rocca: This parameters plays is not aware plasma right in a very exclusive place on a parameter space for plasmas in which what I'm plotting here is on the vertical axis electron temperature on units of electron volts. And on the horizontal axis electron density in 139 00:23:40.950 --> 00:23:42.180 Jorge Rocca: In one centimeter 140 00:23:43.500 --> 00:23:55.320 Jorge Rocca: And what we can see here, of course, this temperature this pressure. So this is temporary to this density. So the diagonal is pressure right when we are at the pressure, about one mega bar. 141 00:23:56.580 --> 00:24:04.740 Jorge Rocca: Which is basically energy density of more than 10 to the fifth job per cubic centimeter. We are in which is called the high energy density plasma regime. 142 00:24:05.160 --> 00:24:15.930 Jorge Rocca: In which we have Plasmas, like like planetary course the whole realm of the National Ignition Facility and so on. And then three orders of magnitude above this log scale. 143 00:24:16.410 --> 00:24:25.650 Jorge Rocca: We have pressures and more than one gigabyte hard energy density of more than 28 joules per cubic centimeter right this is the region this occupy was not a wire right 144 00:24:26.310 --> 00:24:33.990 Jorge Rocca: And in the lab, but that's the region that pretty much only can be accessed right with the world largest lasers, which in fact can create even larger. 145 00:24:34.290 --> 00:24:43.740 Jorge Rocca: Than city. However, there is an overlap on the region that have both plasma and the nanowires can in can get him in principle can get even harder. 146 00:24:44.760 --> 00:24:50.850 Jorge Rocca: So one of the first motivation for us to to investigate this plasmas was to 147 00:24:51.630 --> 00:25:03.000 Jorge Rocca: Generate him intense a flash of X rays incoherent flasher works. Right. Right. And the challenge there is the following is the one irradiated a 148 00:25:03.750 --> 00:25:12.000 Jorge Rocca: Simple example of flat target right with them, you know, intense laser. Pause One forms of plasma. Plasma has a small dimension and will rapidly expand 149 00:25:12.330 --> 00:25:23.100 Jorge Rocca: And the head of the dynamic expansion right we'll add the article. Cool. The plasma sometimes before the collisions can take place and radiation be admitted. 150 00:25:23.550 --> 00:25:27.030 Jorge Rocca: Right, so we want once plasma to be inefficient radiator. 151 00:25:27.540 --> 00:25:36.120 Jorge Rocca: 111 is the radiation lifetime. That is the time that takes for the lectern to transfer the energy to the atoms and it'd be made it on the form of radiation. 152 00:25:36.540 --> 00:25:45.570 Jorge Rocca: To be less than the time that takes the are significantly less than the plasma the time that takes the plasma to expand a huddle and 153 00:25:46.260 --> 00:25:55.650 Jorge Rocca: So when one wants is the radiation lifetime be less than the dimension of the plasma divided by the speed of sound on the plasma. 154 00:25:56.130 --> 00:26:04.320 Jorge Rocca: And therefore the plasma have been describing her nano structure or ideal for this purpose because, number one, they have a large dimension right 155 00:26:04.860 --> 00:26:13.770 Jorge Rocca: On therefore in the heather Nemec time is going to increase and get more time the plant material, plus the 156 00:26:14.640 --> 00:26:30.150 Jorge Rocca: Radiated lifetime with depends on on electron collisions rights inversely proportional to the electron density. So here we have a plasma nano array that has a high density, reducing the ready lifetime and enlarge dimension, right, meaning this this criteria. 157 00:26:31.260 --> 00:26:47.970 Jorge Rocca: So prior to this experiment right X rays from plasmas. A have been produced like would be another 1% efficiency by several groups sided there on the bottom of the slide decent as, as well as well as others. And what we were able to do with 158 00:26:49.200 --> 00:26:59.040 Jorge Rocca: A nanowire raise is achieved conversion efficiency of the other 20% that is here you have conversion efficiency. This is for a 159 00:26:59.700 --> 00:27:13.080 Jorge Rocca: Flat a goal in slab and this is efficiency for nanowire goal nanowire arrays of different nanowire diameters. You can see for an array of 18 millimeter 160 00:27:13.920 --> 00:27:28.560 Jorge Rocca: Goal nanowires we achieve on average around 80% conversion efficiency with the best shots reaching up to 24% right of a conversion efficiency from optical laser right into into X rays. So 161 00:27:29.070 --> 00:27:40.470 Jorge Rocca: This is a nanowire race redeemable for showing them spouses are very intense of flashes of X rays. But can we do for example for radiography right. And here's just one example. 162 00:27:40.980 --> 00:27:49.170 Jorge Rocca: In which an undergraduate student working on on one of them in fact on this project on the extra laser excuse me in the extra resource. 163 00:27:49.440 --> 00:27:57.240 Jorge Rocca: Development Project. He was a bio engineering students. So he's probably had to end up with something that had to do biology. So he brought this was me. 164 00:27:57.720 --> 00:28:07.530 Jorge Rocca: And this is a single sharp right x ray or the was knee showing good level of detail spatial resolution of the order three microns, because the source sizes, very, very small. 165 00:28:07.980 --> 00:28:12.840 Jorge Rocca: Right. And this single shot radiography was taking only resident. I was 30 millennials. 166 00:28:13.440 --> 00:28:20.070 Jorge Rocca: Which as you will see, we have multiple capability, right. So we're using basically 1% or less of the energy of the laser 167 00:28:20.580 --> 00:28:33.930 Jorge Rocca: And of course the interest is as a flash of X rays because second generations right therefore can be done to the entire resolve radiography is of interest to the tech right evolution of rapidly evolving dance plasma. 168 00:28:35.130 --> 00:28:46.440 Jorge Rocca: So what is creating creamy hardens plasma. So the thing immediately comes to mind right is a fusion right a new term production. So we learn how to 169 00:28:46.950 --> 00:28:58.920 Jorge Rocca: fabricate duty rated nanowires and we did that basically by extruding user at polyethylene in a matrix with them, you know, with porous and then we solve in the matrix. 170 00:28:59.280 --> 00:29:13.410 Jorge Rocca: And we end up with array of nano whereas like this is not as beautiful and the one of the metal nanowires right but still in they they meet the conditions for, you know, for an experiment like this. And the idea is that when the nano whereas get heated, they will explode. 171 00:29:14.580 --> 00:29:16.020 Jorge Rocca: They uterine 172 00:29:17.400 --> 00:29:33.060 Jorge Rocca: Basically ions will be accelerated 200 caveats, or even me vs will collide fusing into helium three and producing producing neutrons. So the first thing we did was characterized the ions that are produced with a Thompson parabola. 173 00:29:34.110 --> 00:29:42.540 Jorge Rocca: And on the left you have it pumps a parabola trace a which identify different type of violence on them on the 174 00:29:43.200 --> 00:29:48.960 Jorge Rocca: Other way you have hydrogen rather comes from water vapor. That's always there. Then, then you have the 175 00:29:49.830 --> 00:30:01.530 Jorge Rocca: Deuterium beak and then you have different carbon ions. And you can see that the most energetic ions. A by irradiating a flat target at 8819 watts per square centimeter 176 00:30:01.920 --> 00:30:10.650 Jorge Rocca: Is happening. Maybe they will repeat it up on the nano IRA right and we see the most energetic deuterium ions are above three me we 177 00:30:10.980 --> 00:30:20.760 Jorge Rocca: Given a very good our lab right with the fusion. Fusion very efficient cross section. So to detect the nutrients we built an array. 178 00:30:21.150 --> 00:30:28.440 Jorge Rocca: Of simulator for the multiplier. The factors and put them at different distances from them from the targets. 179 00:30:29.400 --> 00:30:33.690 Jorge Rocca: Sad such a good time of flight measurements and determine the energy of the neutrons. 180 00:30:34.170 --> 00:30:46.650 Jorge Rocca: And of course the plasma, as I said, produce plenty of X rays and gamma rays. So we shielded the detective with 10 centimeters of lab right to identify the X rays and gamma rays right and be able to get that, then the tech the Newton signal. 181 00:30:48.840 --> 00:30:54.090 Jorge Rocca: And these are the results of the measurements in with this is the time of arrival of the natural. Pause 182 00:30:54.480 --> 00:31:05.640 Jorge Rocca: And typical trays look like this right first with first thing that arrives to the doctors are in Islam gamma rays that are able to still go through them 10 centimeters of lead and then 183 00:31:05.970 --> 00:31:11.460 Jorge Rocca: At a certain time delay depending of the location right of that particular factor, you get the new topic. 184 00:31:12.240 --> 00:31:19.440 Jorge Rocca: So this is a plot of time of arrival neutron peak right as a function of this lens of the effective on the target. So 185 00:31:19.800 --> 00:31:37.380 Jorge Rocca: The slope gives you the velocity from the velocity and calculate the northern energy and it is two point 48 plus minus zero point 14 and maybe that coincides right well with two points 45 and maybe energy characteristic of DV fusion reactor. So these are very nutrients and 186 00:31:38.670 --> 00:31:47.040 Jorge Rocca: We compare the number of nodes produced by Martin the array with bombarding just a flat a target of the same city. 187 00:31:47.580 --> 00:31:54.420 Jorge Rocca: City to material. And here's the answer. Basically, right, the neutron peak on them nano array. 188 00:31:54.990 --> 00:32:15.180 Jorge Rocca: On average was 500 times larger right then basically neutral production right on the flash array with about 2.5 10 to six in nutrients per jewel in disarray besides a producing this, you know, extreme plasma conditions also produce extreme fields. And here is a 189 00:32:17.220 --> 00:32:24.510 Jorge Rocca: Few slides on the production, you know, a gigantic magnetic fields. And the reason why there are large magnetic fields can be produced. 190 00:32:25.050 --> 00:32:39.300 Jorge Rocca: On this type of array is that when they also intense pulse arrives, a basic optical feline ization of the wire occurs. So the gap between the wires getting nearly populated by 191 00:32:40.050 --> 00:32:47.070 Jorge Rocca: This free electrons and the laser Paul's a accelerate these electrons towards them. 192 00:32:47.700 --> 00:33:01.680 Jorge Rocca: Towards the substrate and then you create immediately very large charts displacement that has to be compensated. So there are very large return current occurs through the nanowires and these nano. This can be 10s or 193 00:33:03.540 --> 00:33:21.150 Jorge Rocca: Basically my fraction of do a micron square and began to current and a this large currents will produce a class, I started magnetic field. These are a result of particles so calculations you here. See the profile of the wire right and this 194 00:33:22.200 --> 00:33:31.950 Jorge Rocca: Is just a plot of the magnetic field right first of the laser and then here, this is quite an M class I am studying magnetic field that develops due to the return current 195 00:33:32.430 --> 00:33:45.090 Jorge Rocca: And now you have a return current which is very large and very large magnetic field interacting. So you have a very large Lawrence force and a pinch will produce is produced. 196 00:33:45.690 --> 00:33:59.220 Jorge Rocca: So this is a result of the big simulation a nano wire that is initially 300 microns in diameter and is a basically predicted to pinch to a diameter of 197 00:33:59.850 --> 00:34:09.720 Jorge Rocca: Your other 5050 nanometers and on the process of doing that right of pinching to this very small didn't mention the dancing on the nanowires 198 00:34:10.080 --> 00:34:20.610 Jorge Rocca: Right and reaches more than 1000 times the critical dancing right so in the very small volume of the wire when it's reaching more than 1000 times the critical density and 199 00:34:21.960 --> 00:34:38.580 Jorge Rocca: Generating basically this magnetic fields here the unit. The unit some gas. Right. So the simulations predict basically of generation of fields of a actually in several giggles on in the vicinity of the, you know, of the wires. 200 00:34:39.210 --> 00:34:50.910 Jorge Rocca: And then another you know in interesting you know topic right is the generation of extremely highly ionized atoms right and 201 00:34:51.540 --> 00:35:12.060 Jorge Rocca: As you know him, you know, the electron beam iron trap right the Lawrence Livermore National Lab at NIST, and you know, some other places I've been extremely successful in ionizing atoms and generating beautiful spectra have a highly organized items. For example, the event machine. 202 00:35:13.170 --> 00:35:20.160 Jorge Rocca: And someone is not familiar, basically this an electron beam, right, which is very well colonnaded and can be very high energy 203 00:35:21.090 --> 00:35:35.580 Jorge Rocca: That I on ISIS right a gas or atoms vapor that is introduce right in spath and then a an eye on trap basically implemented. So the ions will be trapped right and the electron beam that would be 204 00:35:36.240 --> 00:35:43.380 Jorge Rocca: You know, interacting right with with the ions previously high degree of precision. So even machine have iron is gold. 205 00:35:43.920 --> 00:36:01.770 Jorge Rocca: Right, that has 79 electrons right up to a boat plus 69 right and that takes a lot of energy takes just 100 kilo electron volts to get to go plus 68 nice and then you need a almost 18,000 more EV to organize to plus 69 206 00:36:03.180 --> 00:36:14.190 Jorge Rocca: Know people or even in the even have generated beautiful spectrum, right. However, the density of the plasma is generated here right it's rather low is the other 10 to the 12 207 00:36:14.730 --> 00:36:22.410 Jorge Rocca: And electrons per cubic centimeter, meaning you know 12 orders of magnitude right there below below solid density lasers. 208 00:36:23.010 --> 00:36:30.060 Jorge Rocca: Can do the powerful as you can do a job of creating very high utilization on on plasmas which has much dancer. 209 00:36:30.450 --> 00:36:41.070 Jorge Rocca: Let's say for example in northern the northern Maine is denser than they want to have been, you know, nine or 10,009 and then seven even plasmas. For example, the Omega laser at Rochester. 210 00:36:41.520 --> 00:36:53.370 Jorge Rocca: Was used to erode a goal and produce spectrum in which a goal atoms Iron Eyes to titanium like there is gold plus 57 right and 211 00:36:53.910 --> 00:37:03.570 Jorge Rocca: This was done with nine kilojoules passes from him from from omega, the electron temperature the plasma sexy mated and 6.5 and electron volts. 212 00:37:04.080 --> 00:37:16.350 Jorge Rocca: So with they have a job posts that I show you right already several years ago, we took specter of goals in this particular region between 4.6 and 5.2 213 00:37:17.070 --> 00:37:32.910 Jorge Rocca: Answers, and of course goes, how many electrons. So there the spectrum on this in a part of the spectrum, it doesn't show, you know, nice beautiful individual lines, but it shows him basically UTA right in a race. 214 00:37:34.020 --> 00:37:44.790 Jorge Rocca: And but it's nevertheless possible to a to identify right a part of the mission comes from goal and eyes up to 52 times right 215 00:37:45.120 --> 00:37:57.750 Jorge Rocca: And this on a plasma and this is the result of big simulation. It was the laser competitive very deep into the plasma before the plasma explodes. You can see here the tips turn just flow and the gap being filled so 216 00:37:58.170 --> 00:38:08.760 Jorge Rocca: This is again a very large volume plasma that we were able to organize go up to 52 times right but a of course there is an interest of, you know, 217 00:38:09.210 --> 00:38:14.700 Jorge Rocca: going even further and our simulations that time right predicted that we went to intensive tend to 218 00:38:15.240 --> 00:38:28.440 Jorge Rocca: Tend to 22 watts per square centimeter we scale the intensity right by you know three orders of magnitude. Want to start seeing, for example, flooring like gold right more than 70 times you know i and is gold. 219 00:38:28.920 --> 00:38:35.250 Jorge Rocca: So to do this type of research that I have been talking about. Now it's higher intensities right very highly organized materials. 220 00:38:35.940 --> 00:38:47.520 Jorge Rocca: More neutral production right gigantic magnetic fields we develop, you know, our own pet our laser with developing house right is zero point 85 bed our laser that have the 221 00:38:48.030 --> 00:38:59.700 Jorge Rocca: unique capability of, you know, or, or, you know, rather unique there there are the lessons that can get to this and Robert. In particular, they have apples laser be the Livermore 222 00:39:00.090 --> 00:39:12.840 Jorge Rocca: For the play project in Europe, a high rep, right. So, and the reason okay I you know your mighty lasers or Hercules, we decided to call you know our laser a lab. 223 00:39:13.290 --> 00:39:19.200 Jorge Rocca: For advanced lasers for extreme for dykes right but actually, to be honest, you know, the 224 00:39:20.070 --> 00:39:31.890 Jorge Rocca: Title is an excuse to, you know, to honor, you know, Jorge Luis bar his right, which is my prefer writer on Spanish language which is famous for his short stories. 225 00:39:32.490 --> 00:39:42.600 Jorge Rocca: And board has wrote a very famous short story that's called the lab and the lab right is this little incandescent, you know, this bright ball that 226 00:39:42.960 --> 00:39:53.040 Jorge Rocca: Gentlemen, discovering his basement. Right. And he writes, I saw a small incandescence fear of almost unbearable brightness American unbearable brilliance. 227 00:39:53.550 --> 00:40:00.510 Jorge Rocca: And Borchers which on all his writings right play all the time with with the concept of infinity and time and so on. Right. 228 00:40:01.080 --> 00:40:11.130 Jorge Rocca: What went right that this ball contains entire universe and the entire history of the universe. So, you know, you can basically have the universe. The properties of universe. 229 00:40:11.670 --> 00:40:22.020 Jorge Rocca: The universe right in this small you know I'm Barrow in little sphere of unbearable brightness. So, you know, it was with i thought was proper name for for our laser 230 00:40:22.950 --> 00:40:34.320 Jorge Rocca: So going back to the list itself. The reason we can fire have repetition read it because our amplifiers are not rods. There actually is labs have his lab geometry. So, you have still very large area. 231 00:40:34.800 --> 00:40:44.820 Jorge Rocca: To reuse them is theoretical, but you have very large surfaces were to call is the media is very narrow just one centimeter. So we flow 180 liters of water per minute. 232 00:40:45.210 --> 00:40:58.860 Jorge Rocca: on his lap this lab is in fact just a poem by conventional low cost flash lamps $300 each right and geometry with high water flow is such that you can turn on previous amplify of hurts. 233 00:40:59.340 --> 00:41:05.790 Jorge Rocca: Right, just to leave a safety margin. We operate entire laser 3.3 hurts. The other advantage of lab geometry. 234 00:41:06.270 --> 00:41:14.550 Jorge Rocca: Is that you can inject the women and anger, said the view Paul is the size of its I was with the lab, then you will have taught an internal reflection. 235 00:41:14.850 --> 00:41:22.140 Jorge Rocca: And the beam will make a path like in degree here in which you will average the thermal gradient, right, that usually our limitation. Right on. 236 00:41:22.560 --> 00:41:38.820 Jorge Rocca: On high power lasers. So we build basically eight of this labs, each one givens angels of energy we frequency double it, and just for fun right here is a picture of four of those labs and I'm going to play to you, you know, finding a 3.3 hurt. 237 00:41:42.450 --> 00:41:54.420 Jorge Rocca: I think that every video is not greatly synchronized. Actually, but you get an idea and here on this other short movie, you see the titanium sapphire amplifiers. 238 00:41:54.750 --> 00:42:05.370 Jorge Rocca: being irradiated 3.3 Hertz. That's our third stage amplifier for stage amplifier. And finally, this gets compressed right into this syrup point at what better what Paul side. 239 00:42:05.730 --> 00:42:13.530 Jorge Rocca: I just mentioned. So the laser can fire right in with the boot shut shut him, you know, stability, right. 240 00:42:14.100 --> 00:42:20.700 Jorge Rocca: Before compression 36 you pauses that then we can compress to, you know, zero point 85 you know better one. 241 00:42:21.210 --> 00:42:34.020 Jorge Rocca: And during the amplification they pause maintains a broad bandwidth, such as it can be compressed down to 30 seconds. As you know, we measure with different different diagnostics. 242 00:42:34.590 --> 00:42:47.430 Jorge Rocca: So we have basically in the past that can put in, you know, more than 25 years on 30th 31st or second, however, for most of our experiment with the nanowires we make it to make absolutely sure. 243 00:42:47.880 --> 00:42:59.940 Jorge Rocca: That there is no any pre Paul's meaning not a pause that has, you know, even one one millions or even less of the intensity, because that will destroy the nano era before the main boss arrive. 244 00:43:00.390 --> 00:43:12.960 Jorge Rocca: So to have a very quick pointers past we frequency double the balls into a signal in your crystal. And as you know, the process of a harmonic generation goes with intensity square 245 00:43:13.560 --> 00:43:20.190 Jorge Rocca: So that automatically give us extremely high contrast so we can generate pauses with a conscious of 110 to 12 246 00:43:20.820 --> 00:43:27.480 Jorge Rocca: right on target and make sure the no pre plasmas generated before the high intensity pause arrive. 247 00:43:27.930 --> 00:43:40.830 Jorge Rocca: And then we separate them in remaining fundamental is not double from the frequency of our 400 meter pause using a set of five die growing mirrors that transmit right the fundamental and reflect 248 00:43:41.190 --> 00:43:49.170 Jorge Rocca: Right. The, the blue light. So we end up right it will only blue light on, you know, target. Nevertheless, we could Alberta with the dual 249 00:43:49.560 --> 00:43:59.070 Jorge Rocca: You know that code coding reflecting both fundamental and the second harmonic. So we can do experiments at both when know high contrast is required so 250 00:43:59.520 --> 00:44:09.540 Jorge Rocca: We send them this a contrast boss into target chamber. You can see the laces there on the back right and and a decent F2 parabola. 251 00:44:09.960 --> 00:44:25.830 Jorge Rocca: Short fatherland parabola that can focus the 18.5 centimeter beam. This better world class name into a spot of about 100 microns dimension squared allow us to obtain intensities up to 6.5 10 to 20 watts per square centimeter 252 00:44:26.580 --> 00:44:35.520 Jorge Rocca: A we have recently acquired an F1 parabola that should put us above above them to 10 to 22 in watts per square centimeter so 253 00:44:36.180 --> 00:44:56.820 Jorge Rocca: With this laser, we did several, several experiments. One of them is looking at the electrons that are generated from this a nano were plasmas electrons going on the laser him basically back backwards direction, right. So we build an electron spectrometer and 254 00:44:58.050 --> 00:45:10.980 Jorge Rocca: In this case, right. We then this is for city to nanowires the same one that we used to produce neutrons. Right. In this case, the rap the plasma rapidly explodes. 255 00:45:11.430 --> 00:45:19.350 Jorge Rocca: Creating an overabundance plasma, but the intensity is such right that the plasma becomes rather basically transparent. 256 00:45:19.710 --> 00:45:35.250 Jorge Rocca: Right and the laser balls can penetrate all the way to substrate even right and the fact that the you know the plasma is over, then from the very beginning, right, pretty much of the, you know, of the interaction. So study this interaction for electrons. 257 00:45:36.450 --> 00:45:46.920 Jorge Rocca: We compare right the electrons that we detected that this is the electron spectrum here right this is number of electrons as a function of 258 00:45:47.550 --> 00:45:55.590 Jorge Rocca: electric energy bombarding a CD to flood target writing with the maximum electron energy with a tactic was around 10 me 259 00:45:56.010 --> 00:46:11.490 Jorge Rocca: With what we detected with a nanowires and on the best shot. We saw a car of energy which is you know more than twice as high, but in important is the fact that we saw up to almost 25 times right more 260 00:46:11.970 --> 00:46:22.680 Jorge Rocca: energetic electrons and the characteristic temperature right is my much higher front from them from the nano IRA M. The amount of gamma rays produce 261 00:46:23.220 --> 00:46:33.840 Jorge Rocca: When they strike the substrate right is then consequently much larger than a wire rate than bombarding right flats level, the same material. Now, when this nanowires explode. 262 00:46:34.320 --> 00:46:45.960 Jorge Rocca: Right. The ions are accelerated mostly radio right and acquire very, very high energy and this is again a not a cartoon, but actually search result of a pig simulation. 263 00:46:46.710 --> 00:46:51.990 Jorge Rocca: In which I am trajectories are shown here. So each one of these dots represents a different time. Right. 264 00:46:52.590 --> 00:47:00.960 Jorge Rocca: And you can see how they cloning wires form this, you know, radio, you know, I am being this is results for 510 to 21 watts per square centimeter 265 00:47:01.590 --> 00:47:14.070 Jorge Rocca: And this produce a now a much larger number of neurons, basically. Now we're moving on to 10 to seven. Nutrients. Nutrients per shot, you still have, you know, the proceeding x ray peak right 266 00:47:14.730 --> 00:47:25.980 Jorge Rocca: And this is what happens with the ions, say, in the middle of the wire. But now if we go toward the tip of the wire electrons that leave the wires towards the laser 267 00:47:26.640 --> 00:47:41.130 Jorge Rocca: Create basically a chart separation in basically class I the NSA feel that it starts accelerating the ions up towards the laser and and this is simulation ride of 268 00:47:42.030 --> 00:47:48.060 Jorge Rocca: With an aspect ratio of wires more or less than is done on the on the experiment in which we aim. 269 00:47:48.570 --> 00:47:56.970 Jorge Rocca: In which is acceleration very high energy is predicted towards them in towards the laser. So we do an experiment and 270 00:47:57.390 --> 00:48:10.020 Jorge Rocca: Measure basically the flux of violence and this saturated carbon read run is is emitted them neutrons and protons and maybe you know present on the 271 00:48:10.860 --> 00:48:23.490 Jorge Rocca: Laser bag or direction, leaning towards them towards the laser right and using nanowires as compare if you use, you know, the flat city to target and, moreover, developing experimental setup. 272 00:48:24.660 --> 00:48:35.310 Jorge Rocca: That allows to measure with good resolution, the angular distribution of the of the iron beam we see the assignment was extremely work automated 273 00:48:35.670 --> 00:48:43.050 Jorge Rocca: This was done by putting a very thin piece of stainless steel just coming into a very sharp edge like a knife facing the laser 274 00:48:43.350 --> 00:48:53.580 Jorge Rocca: So you're not, you know, a blade that and on the other side blowing him pieces of C of C 49 right which is a material when on 275 00:48:54.360 --> 00:49:02.400 Jorge Rocca: I will impinge ill will make another whole than with chemistry, then you can develop and enlarge the whole so you can see it on a microscope encounter. 276 00:49:03.060 --> 00:49:09.900 Jorge Rocca: And would you can see that on this piece of see him, you know, car 39 which was place near the access right where the 277 00:49:10.350 --> 00:49:18.300 Jorge Rocca: Actual the laser beam, you have large density violence is striking the director, but on the pieces of fear, Sierra 39.7 278 00:49:18.720 --> 00:49:27.960 Jorge Rocca: A just an angle 7.5 degrees away, right, the number of lines, very small showing that we have a very column ad. I am being around 7.5 degrees. 279 00:49:28.380 --> 00:49:37.860 Jorge Rocca: You know, for the maximum. So we're currently doing on the lab now is using these main to him produce nuclear reactions we target, such as Berlin. 280 00:49:38.370 --> 00:49:49.170 Jorge Rocca: And from there, get a basically a neutron pulses right from from these notes from this nuclear reaction in would normally call right Peter catches came 281 00:49:49.560 --> 00:49:57.720 Jorge Rocca: In with right there. They started to produce you know the picture right we bombard the beryllium. Right. That's the catcher you produce your nutrients and 282 00:49:58.560 --> 00:50:06.570 Jorge Rocca: Now going to metal nanowire right it was a classic malware. So now going to metal nanowires irradiated an intensive 14 to 21 283 00:50:07.050 --> 00:50:16.440 Jorge Rocca: Well, this is again the result of big simulations, or what happens to the laser pause right threads nanowire and you can see that the laser pause read 284 00:50:16.890 --> 00:50:27.840 Jorge Rocca: Over this blog is immediately created and even on the case that the intensity is for 10 to 21 okay this is not sufficiently to produce a little magnetic transparency. 285 00:50:28.500 --> 00:50:35.790 Jorge Rocca: In and therefore, right. The, the label. I really cannot penetrate justice before a lower intensity right 286 00:50:36.150 --> 00:50:44.070 Jorge Rocca: All the way in the narrower however you create immediately extremely dense plasma with very fast electrons. 287 00:50:44.490 --> 00:50:55.590 Jorge Rocca: And the vast fast electrons are in charge. Then on distributing the energy a along the wire so effectively you're still heating Tina volume, according to the, you know, to the 288 00:50:56.490 --> 00:51:09.300 Jorge Rocca: To the big simulation and in the, in the next slide here shows that the amount of energy of the passive by such as being the energy density extremely large. This is the energy density 289 00:51:09.720 --> 00:51:18.630 Jorge Rocca: On gigawatts per cubic centimeter. And you can see that the tip of the nanowires it reaches several hundred gigawatts per cubic centimeter 290 00:51:18.990 --> 00:51:29.070 Jorge Rocca: And then the electrons are accelerated on the street view the energy and along the wire you achieve a relatively uniform energy, the position that is still 100 gigawatts. 291 00:51:29.370 --> 00:51:40.140 Jorge Rocca: per cubic centimeter right way way into the ultra high energy density regime. So with this gold nanowire plasmas will repeated this spectroscopy experiment. 292 00:51:40.710 --> 00:51:56.730 Jorge Rocca: Right, that I discussed before, but now at much higher intensity 310 to 21 watts per square centimeter and a in accordance to, you know, our old you know pig simulations we create extremely highly is gold. So 293 00:51:57.870 --> 00:52:04.380 Jorge Rocca: We are looking now the original between 9.8 and 11 kV so they are. You can see very nicely, you know, 294 00:52:05.490 --> 00:52:18.450 Jorge Rocca: Identifiable lines of near line gold flooring Lego oxen, like, oh, and we see up the lines of a nitrogen cycle, which is 72 times right and ionized goal and 295 00:52:19.200 --> 00:52:29.400 Jorge Rocca: These are the plasma has 15% solid density. We also bombarded with the foil and we achieve similar degrees of ionization by the I was showing us. I will show you in a much smaller. 296 00:52:29.820 --> 00:52:45.570 Jorge Rocca: Volume. So this big basically this is the generation right of 75 ionized go items right on a significant volume on the plasma that is close to a solid density. These was published as few weeks ago on on Nature Photonics 297 00:52:46.350 --> 00:52:52.290 Jorge Rocca: A. So what's electron temperature plasma. Well, one can start getting an idea just doing a very simple 298 00:52:52.620 --> 00:53:04.530 Jorge Rocca: Him in basically least in steady state ionization balance calculation right on which one plus the iron abundance as a function of electron temperature and one sees us from that. 299 00:53:05.310 --> 00:53:11.640 Jorge Rocca: Stay, stay simulation that to get nitrogen like Goal one is to have temperatures about 10 K 300 00:53:12.570 --> 00:53:32.040 Jorge Rocca: Okay. However, the plasma, we have is transcend is very transient right so the temperature to be significantly higher than kV needs to be, you know, at least several 10s of kV right at you know at a solid density. So we're talking here in plasma Lindsay 510 to 23 right electrons. 301 00:53:33.540 --> 00:53:45.360 Jorge Rocca: Should say cubic centimeter actual and so now how large is the volume and with this near solid density. Density plasmas our iron is up to go 72 302 00:53:45.810 --> 00:53:56.460 Jorge Rocca: Well, we use again the trick of putting a tracing element right buried underneath so underneath him a gold foil. This is for, you know, the 303 00:53:57.270 --> 00:54:05.670 Jorge Rocca: Experiments just with solid go we put nickel that we know you know very well how identified helium, like in nickel, like in 304 00:54:06.600 --> 00:54:16.260 Jorge Rocca: Line. Right. And if you have one micron gold foil and you put MECO underneath and you do the spectroscopy. You still can iron eyes. 305 00:54:16.590 --> 00:54:29.040 Jorge Rocca: Nickel to helium like under one migrant ago. However, when you go to. Why don't have my girl. Girl, just barely see the helium like Nick alive right saying that you're not hearing much more than a micron. 306 00:54:30.210 --> 00:54:39.720 Jorge Rocca: Of that on the forum in contrary when you do the same experiment. And now we use our techniques have been able to fabricate wires to composition 307 00:54:40.290 --> 00:54:52.110 Jorge Rocca: Even when we put eight migrants have gone on top of Mexico, we see very intensive mission from helium like Nicole right so indicating basically this class might create it right on him substantial right 308 00:54:52.650 --> 00:55:02.310 Jorge Rocca: In volume now looking at the future game. So, well, how about you know going even further. Right. Well, the big simulation as 309 00:55:02.910 --> 00:55:15.240 Jorge Rocca: A predict that if one has more laser energy and is able to enlarge the laser spot to find microns, right, then a plasma one would create okay we'll 310 00:55:16.200 --> 00:55:29.460 Jorge Rocca: Have atoms are our eyes up to him like goal now right so certain goal plus 77 right so when starting to get, you know, in those two hydrogen like in goal at at solid dancing right 311 00:55:30.360 --> 00:55:44.250 Jorge Rocca: So I basically just want to conclude with some, you know, then basically you know future outlook, right, if one irradiated. You know, big simulation show that one. He raised his nanowires 312 00:55:44.670 --> 00:55:57.000 Jorge Rocca: For example, gold nanowires 55 millimeters in diameter, September solid 13% of them 13% solid density with a 32nd boss at one time to 10 to 22 watts per square centimeter 313 00:55:57.570 --> 00:56:06.960 Jorge Rocca: The wires will get extremely hard, they will explode and will form this by this volumetric hearing right in, you know, a 314 00:56:07.470 --> 00:56:22.230 Jorge Rocca: Multi micron size plasma which with energy positions in a predicted to be up to $80 us per cubic centimeter right and and basically if fractions of, you know, Tara bar and pressure. 315 00:56:22.950 --> 00:56:30.240 Jorge Rocca: Which is pretty exciting. So I want to conclude by a acknowledging right the contribution of many, many people right 316 00:56:30.720 --> 00:56:41.160 Jorge Rocca: They simulations. We're done with them closely observed who have collaborated and now for more than 25 years and then a pic simulations were 317 00:56:41.580 --> 00:56:47.280 Jorge Rocca: Done and running Alex Bob of code, and some of them were done in fact by like his students 318 00:56:48.030 --> 00:57:02.610 Jorge Rocca: Maria Gabriella, a couple looters a faculty member knows when Osiris. She's a visitor every the year and help us to grow the nanowires and and some of them you know other people, you know, we see a young one show you one there, you know, 319 00:57:03.870 --> 00:57:17.190 Jorge Rocca: Basically working our laser facility helps to construct the laser and recall and years of a former graduate student and I suppose luck on, you know, our group, and there are other grad students 320 00:57:17.760 --> 00:57:28.860 Jorge Rocca: In that contribute to our work in Carmen money and you know mine same close colleague made many of the optical coatings of our laser system. 321 00:57:29.280 --> 00:57:40.620 Jorge Rocca: A Mario Marconi collaborated with us for years right on X rays, X. Related development and then in many other many other projects. So am I will basically 322 00:57:41.520 --> 00:57:53.610 Jorge Rocca: leave you with a conclusions. Right. And I want to also show this last picture of our lab right not facing the mountains, but just from the mountains, the other way. Right. 323 00:57:54.000 --> 00:58:00.120 Jorge Rocca: This is the advanced been lab at Colorado State University. Right. And actually, on a 324 00:58:00.600 --> 00:58:10.830 Jorge Rocca: Moment in with the sun was creating you know this bride names right so you know this is not a trick. Does it is a picture actually from the building on front where we have our offices. 325 00:58:11.340 --> 00:58:23.820 Jorge Rocca: In office and you know the lab with the, you know, with the sky in this guy in a beam. So in a thank you very much again for the invitation. And then I thank you for attending. 326 00:58:29.070 --> 00:58:35.310 Alec: Guess it's a happy people are clapping silently with the with the meantime. 327 00:58:36.840 --> 00:58:37.680 Alec: Video 328 00:58:38.070 --> 00:58:39.630 Jorge Rocca: Yeah, be happy to answer question. 329 00:58:39.780 --> 00:58:47.400 Alec: Seminars, yeah. Thank you very much. And I, I don't think it was established the protocols for for the question answer, but 330 00:58:48.540 --> 00:58:49.170 Alec: I think if 331 00:58:50.280 --> 00:58:53.010 Alec: People either use the raise hand function in the 332 00:58:55.170 --> 00:58:57.780 Alec: In the zoom window or 333 00:58:59.700 --> 00:59:11.130 Alec: Just go ahead and ask questions, though, there's a there's a question from Tom Mel horn in the chat already, which is what is the intensity contrast on the multiple experiments and Jimmy. Do you know how good it needs to be. 334 00:59:12.780 --> 00:59:25.920 Jorge Rocca: On the multi multiple experiments were done basically with the, you know, is same type of laser puzzle that we do normally the radiation right with you know with one path which basically 335 00:59:26.160 --> 00:59:29.700 Jorge Rocca: Is an intensity is a contrast of you know better than 10 to 12 336 00:59:30.930 --> 00:59:38.910 Jorge Rocca: And we cannot measure you know directly right the contrast. It comes from the fact that we have measured the contrast of our a phone. 337 00:59:39.570 --> 00:59:48.900 Jorge Rocca: I mean, as you have said, we cannot measure directly the contents of our second harmonic. Pause But we infer from the fact that we have diagnose him, you know, careful 338 00:59:49.260 --> 00:59:58.500 Jorge Rocca: Carefully the contrast our fundamentals and then take into account that you know things go as i square right on the, on the, on the doubling and a 339 00:59:59.550 --> 01:00:07.320 Jorge Rocca: And the other. The other thing I should add right is addictive. The contrast. Not good. Okay. With this nanowire plasmas you immediately see it. 340 01:00:07.890 --> 01:00:17.670 Jorge Rocca: If something went wrong right have you, do you know the experiment with the fundamental we poor contrast. For example, these very strong admission from helium law like 341 01:00:18.900 --> 01:00:24.780 Jorge Rocca: You know lines right immediately go washes away. And so, yeah, it's a very high contrast is necessary. 342 01:00:26.640 --> 01:00:32.940 Alec: Can see there's a hand up from Nick. Nick Pisco ski jump to ask question. 343 01:00:34.110 --> 01:00:35.490 Nicholas John Peskosky: Yes, Dr Okada question. 344 01:00:36.720 --> 01:00:47.580 Nicholas John Peskosky: Given that these are essentially Nana fabricates all targets is their fundamental limit on how many you could put in a spatial ray. I mean, what is your maximum team will shot right, given that you got a three tiered system. 345 01:00:49.080 --> 01:00:50.670 Jorge Rocca: Well, basically, you know, for 346 01:00:50.670 --> 01:00:51.390 Jorge Rocca: Now, right. 347 01:00:51.900 --> 01:00:57.990 Jorge Rocca: Pretty much all the minimum and I know why experiments, you know, show we're pretty much in a single shot experiment. Right. I mean, we 348 01:00:59.640 --> 01:01:07.290 Jorge Rocca: We normally fire brigade this nano targets in a either have injured or one inch templates. Right. 349 01:01:07.950 --> 01:01:17.670 Jorge Rocca: And a but you need to move right the of course dropping, you know, and then I mean he radiating this with such intensity is equivalent to maybe to dropping a bomb in the forest. 350 01:01:18.330 --> 01:01:27.420 Jorge Rocca: Basically, you know, you'll destroy you know and significant fraction of the forest. So we move you know fraction of a millimeter the target right 351 01:01:27.750 --> 01:01:38.700 Jorge Rocca: For them, you know, for the next shot and in some cases along the plastic nanowires we moves in a few millimeters right there. The target between, you know, between between shots right 352 01:01:40.350 --> 01:01:48.990 Jorge Rocca: So I'd say these are you know proof of principle experiments in some of the techniques that we're using to forget is nano yrs 353 01:01:49.770 --> 01:01:59.310 Jorge Rocca: are prone to, you know, to be scale into strips. For example, right. And once the nano targets are, you know, fabric of their stuff. They're pretty tough. 354 01:01:59.880 --> 01:02:07.860 Jorge Rocca: You know, in fact, when we started to deal with this you know him to do electron microscopy. We go to the campus right show this picture, a few miles away. 355 01:02:08.670 --> 01:02:13.680 Jorge Rocca: And a graduate student was taking the nano whereas women on a button motorcycle bike right 356 01:02:14.430 --> 01:02:20.400 Jorge Rocca: And at the beginning. We started with this, say, oh, gee, you know, there's no worries shaking read, then they're going to get their own you know 357 01:02:20.910 --> 01:02:36.990 Jorge Rocca: In preterm right now they are incredibly tough right so I imagine that one could produce for example strips, right, like a tape. Imagine run of, you know, with this structure thread and that you could, you know, that it would be amenable to, you know, height represents a 358 01:02:38.550 --> 01:02:43.920 Nicholas John Peskosky: Follow up question, do you grow these through and be like a fit process monitor know 359 01:02:43.980 --> 01:02:44.880 Jorge Rocca: No, actually. 360 01:02:45.900 --> 01:02:56.970 Jorge Rocca: Actually, we in the metal nanowires we grow by electrode plating. Right. So what we do is we have a porous matrix, right, and a, let's say you want to 361 01:02:57.390 --> 01:03:07.710 Jorge Rocca: Grow nanowires of nickels, or gold, you know, for example, you that you a vaporizer right or it's better. I think layer. Go right and then you put on an electrode plating bass. 362 01:03:08.250 --> 01:03:19.590 Jorge Rocca: So basically the voice right and the force matrix will just grow by electrode plating like you do any electric plane right and then you dissolve the Portsmouth matrix and that within with right 363 01:03:20.730 --> 01:03:39.870 Jorge Rocca: They once the plastic nanowires the CD to of course you know kind of do like to bring those are done by actually melting or, you know, hitting the CD to write and bill becomes, you know, fluid and extruding them through, you know, a porous matrix that then again is again the slope. 364 01:03:41.820 --> 01:03:46.050 Alec: So Tom Horn has a question at hand up in the in the chat. 365 01:03:48.180 --> 01:04:01.800 Thomas Alan Mehlhorn: Now, Jorge, great, great talk impressive results. I was just curious whether you would have the ability to make these nano wires or on 366 01:04:02.580 --> 01:04:17.070 Thomas Alan Mehlhorn: And whether you've thought about trying to look for P boron 11 reactions and you have your Thompson crabbers where you could look for measuring alphas, as well as your car 39 capability. 367 01:04:18.090 --> 01:04:24.240 Jorge Rocca: Yeah, it was a thank you very much a well him. 368 01:04:24.600 --> 01:04:39.120 Jorge Rocca: You know, I guess boerum you know probably gonna be like replayed it so needs to be some other you know technique. And yeah, we have not we have not in, you know, and actually, you know, look into that. And yeah, it's an interesting suggestion. 369 01:04:44.850 --> 01:04:59.730 Alec: Okay, I don't see any other hands up in the chat at the moment. I just got a couple of quick questions myself. One is, did you control this the spacing of the nanowires at all, and if so, what would you expect, how would you expect that would change the interaction. 370 01:05:01.560 --> 01:05:14.700 Jorge Rocca: Yeah we control the spacing basically a controlling write them a density of holes right on the, on the, on the matrix, right, and we have made arrays between em. 371 01:05:15.990 --> 01:05:25.440 Jorge Rocca: 7% solid density and like 30 some percent no solid density. Right. And one thing that changes. 372 01:05:26.490 --> 01:05:39.150 Jorge Rocca: Is the interviewer spacing. Right. And then the pending what you're trying to do right one case or the other, right, maybe, you know, might be better if of course you want to recreate 373 01:05:39.930 --> 01:05:55.800 Jorge Rocca: Highest Nancy possible right you go with the highest density, but there are applications. For example, in particle acceleration in which you're much better off interacting with them no more limited number of nanowires so yeah so that's one parameter to play with right then. 374 01:05:57.090 --> 01:06:13.230 Jorge Rocca: were dancing therefore interweave spacing. Right. The other one is the wire diameter right that can also be control and we have basically build malware raise between em a smaller 30 in nanometers in diameter. A up to one micro 375 01:06:16.110 --> 01:06:24.690 Alec: And you mentioned this, this pinch effect that happens with the wires which compresses them then they explode as well. 376 01:06:25.140 --> 01:06:38.820 Alec: And it's just wondering about the interplay between these two processes. I mean what what control. So under what conditions where you get them to implode. When will they explode or is it just a time thing that initially they compress and later on they explode or 377 01:06:39.810 --> 01:06:48.180 Jorge Rocca: Yeah. What, in essence, in essence, is a bench. Right. Yes. Right. So, you know, I think, you know, I mean, 378 01:06:48.870 --> 01:07:02.670 Jorge Rocca: You know, and Sir or the BRICS nations Prince pretty much the same dynamics of the recipients right you have the Lawrence forth right compressing the wire and building up pressure right and then you get to a point, right, and which you know you balance that right 379 01:07:02.700 --> 01:07:03.150 Alec: Yes. 380 01:07:03.360 --> 01:07:10.590 Jorge Rocca: And as the magnetic field decreases the right then, you know, then the plasma. Will you know will just expand 381 01:07:11.670 --> 01:07:15.420 Alec: But, but is a. So does it depend on the material. I think I was wondering, you know, 382 01:07:15.480 --> 01:07:23.370 Jorge Rocca: So I'm gay. Yeah, I mean, there's yes several variables that play place on the material right this is is you know it's one of them. 383 01:07:23.970 --> 01:07:32.970 Jorge Rocca: And then, you know, but it's interesting you know we have been in a plane with pinches for a long time. Right. We started with a couple of this chart to make software licenses. Right. 384 01:07:33.450 --> 01:07:38.340 Jorge Rocca: And those were pinches looking at the 200 microns in diameter, right. These are benches that are, you know, 385 01:07:38.790 --> 01:07:47.520 Jorge Rocca: Basically 10s of nanometers right there in diameter, but some of the physics right thats related and then one goes to another, go to the other extreme right 386 01:07:48.060 --> 01:07:57.930 Jorge Rocca: And and I used to have a slide in. Boom. This talk in a, you know, with without this you know galactic pinches or astrophysical pinches lightyears dimensions. Right. 387 01:08:00.810 --> 01:08:01.170 Okay. 388 01:08:02.790 --> 01:08:03.030 Mark Kushner: Oh, 389 01:08:04.200 --> 01:08:07.710 Mark Kushner: Alex, this is Mark on reserve, the last question. 390 01:08:08.010 --> 01:08:25.320 Mark Kushner: Okay. All right. How sensitive is the alignment that the lasers coming in perpendicular to the substrate parallel to the nano wires, the source of my question is now, you can imagine lining the inside of a whole ground with nanowires 391 01:08:26.520 --> 01:08:27.990 Mark Kushner: And the angle of incidence 392 01:08:29.370 --> 01:08:35.610 Mark Kushner: Isn't perpendicular and does that gain you anything is are you very very sensitive to that angle. 393 01:08:36.360 --> 01:08:44.040 Jorge Rocca: And, well, that's a good question. And the answer is no, actually, if you build the target. Okay, which 394 01:08:45.330 --> 01:08:57.780 Jorge Rocca: Normally we ready. These are normal insolence. Right. And we have the luxury of doing that because we are working with second harmonic. Right. That will not feedback right into the laser and destroy your laser and but 395 01:08:58.920 --> 01:09:07.320 Jorge Rocca: On experiments we have done basically a tilting the target right on, you know, on purpose. And for example, the ones that we did to detect 396 01:09:07.950 --> 01:09:20.160 Jorge Rocca: You know, the electrons that are he was tilted you know 15 or 25 degrees right a you have you have substitution, you know, for example, if you tell 15 degrees you get you can pretty much the same result. 397 01:09:21.300 --> 01:09:27.630 Jorge Rocca: And after you start to feel Morea you'll see changes, you will see it better not behaving as a as a 398 01:09:29.100 --> 01:09:34.620 Jorge Rocca: Normal incidents, you will align you know structure. So yeah, so there is there sounds 399 01:09:35.850 --> 01:09:37.020 Mark Kushner: Great Thank. Thank you. 400 01:09:38.250 --> 01:09:38.550 Mark Kushner: Okay. 401 01:09:39.000 --> 01:09:39.750 Alec: Thank you, Mark, and 402 01:09:41.010 --> 01:09:48.270 Alec: I think we should close now if I could just ask everyone to unmute their microphones and 403 01:09:48.450 --> 01:09:51.090 Alec: All clap and thank our speaker for 404 01:09:51.660 --> 01:09:57.570 Alec: Great talk. Really appreciate it. Thanks. So hopefully we'll get some something if the live audience. 405 01:09:58.440 --> 01:10:00.090 Jorge Rocca: Well, again, again, you know, 406 01:10:00.120 --> 01:10:16.260 Jorge Rocca: It. Thank you so much for the for the invitation right and I enjoy the entire day and I thank you for, you know, we're taking part of the on the top and hope and hope to see you all in a you know in person in the not too distant distant future. 407 01:10:18.090 --> 01:10:18.570 Alec: Thank you very much. 408 01:10:19.230 --> 01:10:19.560 Jorge Rocca: Thank you. 409 01:10:19.860 --> 01:10:20.310 Thank you.