Steven Francis Nagle: today for Rogers. We have vikas anant with us remotely, as you can see
Steven Francis Nagle: up there on the screen. Not well, not yet, but he will be there.
Steven Francis Nagle: He is mit. He was in Carl Bergeron's group and working on what we'll just say, Nano architecture stuff.
Steven Francis Nagle: and he can describe more if he wants
Steven Francis Nagle: and I guess almost 15 years ago. Now you founded photonspot correct.
Steven Francis Nagle: and he'll be talking with us today about a few different topics related to life outside Mit and beyond grad school
Steven Francis Nagle: somewhat related to his single photon detectors, and maybe a little bit of lab automation.
Steven Francis Nagle: But let's just sit back
Steven Francis Nagle: and enjoy
Steven Francis Nagle: so welcome because and in a moment I'm going to turn it over to you. So just hang on one second.
Rodgers RLE Lab: [...] So over to you, because.
Vikas Anant: Okay, thank you.
Vikas Anant: All right. Thank you. Everyone for coming. I'm going to start off by just telling you a little bit about what we do. This is photon. Spot really has 2 personalities. One is we make cryostats, and the other is we make superconducting Nanowire single photon detectors. But the real goal is to build
Vikas Anant: scientific instruments for for R&D,
Vikas Anant: the the talk I'm gonna give today. I haven't given it before.
Vikas Anant: But it, it kind of originated from how I organize
Vikas Anant: photos on my computer, actually. So I just use Iphoto, bring all the photos in. And when I'm looking through this, I see interspersed pictures of cry stats with pictures of kids and dogs. And and you know, also stuff like that.
Vikas Anant: So this, really is a story about how you know life evolved with with all of that in a little bit. But but I'll mostly focus on the tech. But just to show you here the company, I I started this in December 2,009.
Vikas Anant: that logo I drew at night on. I don't know. It was December first, st or something like that.
Vikas Anant: With all these little dots, and and the logo itself was easy to put together cause I didn't have to think too much. It isn't terribly imaginative, you know. There's a lot of Logos. It turns out with dots. But the idea was, you got this spot kind of like the hotspot that you have with a Nanowire detector, and, you know.
Vikas Anant: ends up there anyways
Vikas Anant: So 6 months before that my daughter was born.
Vikas Anant: And so she's pretty much as old as the company
Vikas Anant: April was about when I quit my day job. So I I was actually working I started the company wrote a proposal, and
Vikas Anant: April Fool's Day we were told that it was selected by the government
Vikas Anant: and so shortly after that. I think maybe a month or 2 after that is, when I
Vikas Anant: I quit my job
Vikas Anant: and did this full time. So
Vikas Anant: that time was not necessarily the best time to quit.
Vikas Anant: some of you. If you're in your early twenties, you probably. Don't remember this. But
Vikas Anant: there was a global, you know, housing crisis recession
Vikas Anant: you know, unemployment. So July 2,007 is when I finished my Phd roughly thereabouts, and then
Vikas Anant: you know the the second dot that's at 9.9% is when I started the company, and it wasn't that much better when I quit my job.
Vikas Anant: So but that's to say, you know, recessions didn't. I don't know how much they affect the decision, but
Vikas Anant: to quit. But yeah, anyhow, so the way it it worked is, you know, once this program got going
Vikas Anant: you know, started to buy stuff and build stuff. The plan from the beginning wasn't to actually
Vikas Anant: make our own crystat. The the project was about integrating a crystat with detectors and using it for
Vikas Anant: looking at the the project involved looking at emission from transistors.
Vikas Anant: for for the integrated circuit industry. So since we're close to Halloween. So that's you know, my daughter. When she 1st started to walk, it was the 1st day she walked.
Vikas Anant: and so she is like very proud of the fact that she wasn't holding on to anything. And then the the picture on the bottom that's when we received a unit that we purchased from a vendor
Vikas Anant: and so my 1st problem that I encountered when we got this thing is how the heck am I going to take this thing off the pallet I was on my own, and the compressor weighs about.
Vikas Anant: you know, I don't know. 200
Vikas Anant: between 100 200 pounds. And I'm like, how am I gonna lift this right? So thank goodness for Mcmaster, you can order a reverse. Boom, Crane, and it shows up the next day to do that. So that was nice once we put it all together. It looked like you know what you see on the right.
Vikas Anant: so I just wanted to talk a little bit about some of the design characteristics, and what the intention was and what it became. So like. I said, we didn't make this. I, you know, had a company build this for me, and I told them, Hey, look! You know I'm on my own. I want to be able to
Vikas Anant: open this thing up myself, and and so you gotta make it easy for me. And you know, we we talked. And it's like, Okay, I want to be able to flip it over. Take things off, and you know, because I gotta deal with little screws and stuff
Vikas Anant: I don't want to be doing all that stuff upside down. So they, you know, came up with this thing where there's this big lever that you turn kind of like on a on a mill.
Vikas Anant: and then it would flip it over, and then you had to take it apart.
Vikas Anant: There were all sorts of problems with this thing from a design standpoint
Vikas Anant: one of the things was to take it apart. You had to. I found this out later. Once I received it.
Vikas Anant: To take it apart, I had to desolder some wires to a connector, so I had to unscrew this connector. There wasn't much slack. I had to desolder some wires, and and then I could take it apart, because the way that they had it the the feed through was on the part I needed to remove so that was dumb.
Vikas Anant: But you know, and I, from what I could tell the source of the reason to do that was probably to save about $200. You could buy a feed through, you know, Connector, that I could have just unplugged and and on both sides. But for whatever reason these guys decided to buy connector and and just glue it in place. So that was one issue there, there's a few others. But any case
Vikas Anant: we shipped it. So this is the the next kind of thing that you need to worry about. If you're making product and shipping.
Vikas Anant: how is it, gonna ship? How is it not gonna break by the time it gets there? You know, we had someone come in and and make a crate
Vikas Anant: and then when it got there it was put to use. So this is one of the partners was Ibm, and and they use this along with their microscope to image some transistors. When when transistors switch, there's some emission that happens
Vikas Anant: in the
Vikas Anant: near ir to, you know, closer to the mid ir and
Vikas Anant: And so that's you know. That signal was fed into the crastad! It went into detectors that were actually made in Carl's group at Mit
Vikas Anant: and
Vikas Anant: you know, and and actually did its thing. So that was in June of 2012.
Vikas Anant: at the same time, while that was happening there was stuff happening in the
Vikas Anant: sort of you know, in the detector side of things there were some very exciting developments. So in 2011
Vikas Anant: there's a paper that was published at by NIST
Vikas Anant: Where they made these detectors out of a material called toxin psilocide
Vikas Anant: which is an amorphous superconductor.
Vikas Anant: But what was interesting to me when I read this paper. So a couple of things. So when I was at Mit, I did a lot of Fab, you know, part of my thesis was on making detectors.
Vikas Anant: So when I see a detector like this, a couple of things came to mind. 1st of all, a lot of detectors we made were quite small because our yield, you know, wasn't that great? So we'd made detectors that were like 3 by 3 microns? Here's 1 that's 16 microns. That was interesting.
Vikas Anant: When I actually look at the sem of this.
Vikas Anant: I mean, it doesn't look that great. There's all sort of splodges and stuff. I mean that some of that might be from imaging. But you know, I was like, Okay, this is the image they put in this paper.
Vikas Anant: No, okay. And then, what was more interesting. There's a a couple more things if you look at the the figure on the bottom. Right? Figure E,
Vikas Anant: you see the count rate, and it kind of flattens out and
Vikas Anant: that was interesting. That's not something that we saw before. When I was in grad school. That was those, you know
Vikas Anant: wasn't
Vikas Anant: so easy to see. There are, you know, other figures from this paper where you know, if you look at the figure, the figures on the on the top. You have this detection efficiency which hits 20%.
Vikas Anant: And you see this flat plateau region. So that's you know, that's
Vikas Anant: quite interesting. So that's basically what that indicates is when the photons hit the detector
Vikas Anant: above a certain bias current, the efficiency doesn't change and turns out when when they did the calculations, you know, almost every photon that was absorbed was being detected.
Vikas Anant: So their device only had, roughly speaking, you know, if you look at the bottom plots there, let's say 20 or 30% you know, absorption essentially. And they're detecting almost all of them. And that was pretty remarkable
Vikas Anant: so I looked at this. And I was like, Okay, well, we're gonna hit, you know, some big numbers. Soon. I think 90% is happening soon. And then the other thing that you see when you look at this thing is
Vikas Anant: the temperatures here are cold. They're not at 3 3 and a half, Kelvin. They're not. It's barely sort of working, even at 1.6 looks like the sweet spot might be
Vikas Anant: below one
Vikas Anant: so so that led me to say, well, I think we need to build the cryo that didn't go down that cold. The kind of cry they used in here was.
Vikas Anant: you know, kind of large and and expensive so I figured, that's probably what we need to do. And so that's what we did. So by January 2013
Vikas Anant: we'd built such a cryo, and this is what it looked like. And so.
Vikas Anant: and there's my scale bar on the left there, my daughter on Halloween in 2,012.
Vikas Anant: So she's gotten a bit bigger and this thing was
Vikas Anant: You know something we built in house at this point. We didn't we stop, you know, when I the thing I learned from that other cryo is that. Well, if you know if this is what people are making, I think I can do this, and probably do this a little better, and do it the way I want to do it.
Vikas Anant: And so we built our own thing. So my thought was, these things need to be in some kind of a rack, because there's other equipment there. So that's you know, we kind of built our own little thing there. And you can see the motif of trying to flip this thing over, take things off, is also there. So you can. If you look in this picture over here
Vikas Anant: you can have it go 90 degrees and pull the can off, and then flip it the rest of the way, and and kind of mess with it. Okay, so that's the other part
Vikas Anant: the the story with this thing is so in late January that year there was a conference that happens every year called photonics West. I don't know if you've ever been to any of you ever been to photonics West. This is a massive conference.
Vikas Anant: going to the trade show on that conference is like going to a mall. It's just like, you know, never ending. There's suppliers that do all sorts of things in the optics world.
Vikas Anant: So I I, you know, brought this thing up in a minivan and rolled it in. And
Vikas Anant: you know. Put it on display and see what people say. Most people walk past. It didn't even notice or care what it was. That's fine. The few people that stopped there there were some people from this that stopped there, and they said, Hey, look at this thing! Oh, it gets below! So the thing with this thing is it gets below one Kelvin.
Vikas Anant: And so they stopped and looked at this thing and said, Oh, wow! This thing is pretty small, you know, for something that gets below one kelvin
Vikas Anant: I had people in the optics world who are interested in single photon detectors. You know the handful of people who stopped
Vikas Anant: buy it. And they said.
Vikas Anant: Oh, wow! This is kind of big, you know.
Vikas Anant: Basically, where am I going to put this thing in my lab?
Vikas Anant: So, you know. So you have different feedback from different people. And
Vikas Anant: I figured well, I should probably listen to the optics people. Because, you know, they probably, those are the labs that it needs to go in.
Vikas Anant: And so this is January 2013
Vikas Anant: the performance of the fridge. The serpent fridge that was in there. So the the kind of cooler that you need to get down below one Kelvin, you can't do this with off the shelf components. The the prior coolers that you can buy get you somewhere north of 2 Kelvin. So 2 and a half Kelvin something like that
Vikas Anant: to go below. You need to.
Vikas Anant: essentially the easiest way to do it is to pump on helium. And so you have a vessel that has helium gas in it that we then liquefy, and then we pump on it
Vikas Anant: so the kind of unit that we built. It's self contained inside the cryo, there's no
Vikas Anant: yeah. Semicole
Vikas Anant: back. Sorry. Yeah. There's no, you know, helium tanks or pumps outside that the pump is contained inside. It's an absorbing pump. But anyhow, it it let you know. It's also the other feature with this thing or bug is that it doesn't stay cold continuously. There's a duty cycle. So this thing stayed cold for.
Vikas Anant: let's say, 11 h, something like that. If if there was nothing attached to it, and a lot less if you put on actually a load on there. So let's say about a working day.
Vikas Anant: was all we could. You know, muster in the in the 1st rev of this thing.
Vikas Anant: So which is, you know, it's enough for most experiments. But you know ideally, this thing needs to go a lot longer. So their prototype wasn't perfect, but it worked
Vikas Anant: so the
Vikas Anant: the other thing that happened in again at the similar timeframe was the packaging of the detectors.
Vikas Anant: you know, was essentially solved. So in later in 2011, this is a paper. This is from a paper that was also published at NIST
Vikas Anant: the
Vikas Anant: you know, the way in which you couple light onto the detectors was, you know, was an issue you have to. The detectors are you saw in that picture, you know. Let's say, 10 or 20 microns, and you're trying to couple light from a fiber that might have a core size. That's a similar diameter. So let's say, about 1010 ish microns
Vikas Anant: so you need to do micron scale alignment that's robust to when it gets pulled.
Vikas Anant: and this is a challenging problem. It's a, you know, potentially expensive problem. If you start using piezo stages, and so on. Xyz alignment to actually do it.
Vikas Anant: And then you have to worry about whether alignment sticks when it gets cold, because there's thermal contractions that happen.
Vikas Anant: So the the clever thing that the guys at NIST figured out was, Well, let's take advantage of some of the components that were developed for the fiber optic industry that have extremely good tolerance. So when you're mating 2 fibers together, 2 fc. Fibers, for example, in a you know, Fc coupler, that you can buy from Thor Labs for a couple of dollars.
Vikas Anant: You're actually doing.
Vikas Anant: you know, submicron alignment
Vikas Anant: which is remarkable. The way that works is the concentricity of where that fiber is in relation to a ceramic cylinder is remarkably good. And the outer diameter of that cylinder is 2.5 plus minus a half micron, you know. So you're putting these 2 cylinders together, and there's this ceramic split sleeve
Vikas Anant: where they, they, you know. Come in together, and you you do sub micron alignment that way. What the NIST guys figured as well. Why don't we make the dive of the detector into this lollipop shape, or I like to. I'm a tennis person, so I like to call it more like a tennis racket, because you got the part in the middle. That's the sweet spot. That's where the detector is. Right in the middle of that of that racket.
Vikas Anant: And so you plug the fiber in the die is perfectly, you know, lithographically defined to have those dimensions, and you get excellent mechanical alignment that is so-called. You know it's self aligned essentially. Once you have it in there, you don't have to, you know. Move any anything around to align it as long as the lithography is good. You're good. So this they did this for tes detectors. The reason that this works is that you could do this deep etch.
Vikas Anant: It's a deep reactive ion edge to actually define the shape of this die. And that is a process that is very well known.
Vikas Anant: And you can basically buy a machine to do this but only for silicon.
Vikas Anant: so the key was to make detectors that you could. Then you could grow on silicon. The other part, I didn't talk about you, you know, when I was in grad school we didn't make detectors grown. Silicon Silicon doesn't have a good, you know, in to grow the material you need lattice matching and so on. And you just, you know, we would have terrible yield even when we grow it in an ideal way. But this this wasn't the way.
Vikas Anant: But since you have this new tungsten suicide material, you could do it. And so there you go. And then, just a few years later practical Nanowire detectors were here. So this is in 2013. There's a paper where the people at NIST and Jpl.
Vikas Anant: Published, where
Vikas Anant: they exhibited, they were able to to see over 90% efficiency.
Vikas Anant: Which is, you know, pretty amazing. A couple of really cool things about this paper
Vikas Anant: one is
Vikas Anant: the story goes, is as I heard it. When they 1st measured this detector they measured over a hundred percent efficiency. So they knew they had a good one.
Vikas Anant: But they, you know, they're NIST, so they can't. They have to figure out what's going on. So it took them quite a while to figure this out. The people involved in this. So you know all the names that you see here.
Vikas Anant: I don't know, more brilliant and smarter people on this planet.
Vikas Anant: So we were actually extremely, you know.
Vikas Anant: fortunate, and especially to have people at NIST interested in this technology. I would say, you know, these are the most meticulous experimentalists that
Vikas Anant: you know. That, I've come across. So having people like that
Vikas Anant: worry about. You know, where is that 1% like what you know care about these kind of metrics is something that we've benefited a lot.
Vikas Anant: from this and you know one of the people I'll single out here is the La. You know, the the last author on here. Say, Wudam he passed away recently, but he
Vikas Anant: was, you know, quite a force of of nature, as far as you know. Pushing this technology. And you know, practically the reason why photon spot and other companies exist is because of a lot of the efforts that that he did
Vikas Anant: so so that being said, you know, over 90% is is pretty awesome.
Vikas Anant: I want to just make a point about the yield. So the issue with that earlier paper I showed you with with the tongue seal side. It wasn't very clear. Was this a hero device, or, you know, did they actually have yield. They didn't really talk about yield at all in that paper.
Vikas Anant: This is a plot from A, you know, a figure from paper back when I was at Mit. This is from 2,007 used a different superconductor, called nibm nitride
Vikas Anant: and these were small devices, and these measurements were made by Jamie Kerman, who's at mit Lincoln lab.
Vikas Anant: also, probably one of the most amazing experimentalists that I've I've come across. He measured 132 devices this was days of nonstop measuring, you know. If I ever went there, I was like, Wow.
Vikas Anant: you know, this is this is crazy. And but you know, if you look at this thing, there are those few hero devices that are on that last you know. plot right over here right? And that are the best ones. There is some cluster of ones that are okay. And there's a whole bunch that aren't
Vikas Anant: and the other part you can see in this B thing here is this doesn't flatten out. It just kind of keeps going up.
Vikas Anant: Even though you're at 1.8 Kelvin. So that was state of the art back. Then.
Vikas Anant: if you looked at this paper, they didn't measure that many devices, you know, certainly not 132. But if you look in these columns, these are different Fab runs. They did different device parameters, pretty large devices.
Vikas Anant: and they tested 2 and yielded 2.
Vikas Anant: They tested.
Vikas Anant: you know, 3 here and yielded one. And this is it for you that for I was like, Okay, this is pretty amazing that you know, for me. Looking at this, this is now telling me that this is viable. You don't have to. It's not a needle in the haystack problem. You have to test hundreds of devices, and then only, you know, you could only sell one of them right? So that was that was pretty neat
Vikas Anant: or I shouldn't say neat, transformative.
Vikas Anant: The other part that I saw in this paper was similar to what I was expecting before is that you know you do need to be cold. If you look at the top plot here. This is how the efficiency changes as a function of bias current on this axis and temperature on the other. So around 2, Kelvin, you see the efficiency go up, and you barely see this thing saturating
Vikas Anant: as you get colder. You see the saturation. And you know, when you're around about this green curve over here there's plenty. The current density has, you know, pretty much doubled.
Vikas Anant: As you get colder. So there really isn't that much more to be gained to to go over to, you know these are, maybe dilution fridge temperatures. But this temperature is is close to where you want to be.
Vikas Anant: So again, this is 2013 we actually had a cryo that, you know, could do this. So we built our own as well. So here is a wafer again that has that, you know this lollipop tennis racket, you know dies that that we edged we packaged it. It looks like this. So that's about the size of your of your thumb got a fiber coming in, and a collect cable in the back.
Vikas Anant: and this is, you know, close to it may well have been the 1st pulses that we saw from this detector.
Vikas Anant: There's, you know, a trace up here. These are the laser excitation, you know, like a pulse laser we're sending in. And this is the pulse from the detector. So that's the you know. That's where you know, you've had a photon.
Vikas Anant: So that was cool. Obviously, there's signal noise issues things to figure out. You know, this is in Jan. Feb. Of 2013, when we came back from Botanic West.
Vikas Anant: So the other thing that happened when we came back from photonics West is that
Vikas Anant: The folks at Jpl contacted us and said they need a cryostat and they needed it for a NASA mission, which is cool and they need one now. Because the Mission was going to launch in September, and we're sitting in February. And they kind of need it like right now. And if any of you guys know anything about, you know ordering
Vikas Anant: price stats is they're not off the shelf typically it takes, you know.
Vikas Anant: 10 months, 3, 4, 5, 6 months, even a year. Sometimes, if you're if you're getting something very custom
Vikas Anant: so to have a crash that you know right away was
Vikas Anant: well, we had one, right? So we we essentially, you know, sold it to them. And on September 6th this
Vikas Anant: the mission which was to do lunar communication from the moon. So there's a satellite that was orbiting the moon on its own little Science mission. And then, as a tech demo, they had a laser on it, pointing back to earth, going into cryostat. So our cryostat was used by Jpl. There's a different effort. That was the primary effort at Mit Lincoln lab
Vikas Anant: to do laser com a couple of cool things side. You know things about this project. So this is a Minotaur rocket which was essentially repurposed intercontinental ballistic missile
Vikas Anant: which was pretty cool. So if you actually saw this launch, it wasn't like the space shuttle, you know, when it launches nice and slow this thing goes, you know, pretty fast. So so that's pretty cool the mission was a success, you know, and it was really the first.st you know.
Vikas Anant: test of these detectors for for doing optical calm from, you know, space, you know, you're you're not at Low Earth orbit here, you're actually out a good distance.
Vikas Anant: And yeah, the you know. The the light went from the satellite
Vikas Anant: and then got coupled into telescope. And it went into fiber. And then it went into this thing.
Vikas Anant: So that was in October through April, where they closed that link and
Vikas Anant: and and it was a success. And the other thing is, you know, there was heroic amounts of work. So I mean, we had a crash stat built, and we handed this off, and you know our work was was done, and you know it was very fortunate that you know we were kind of right place right time and for for both parties but once they got this thing they had to put this whole thing together, you know.
Vikas Anant: get it qualified. And and this is some heroic work for the folks at Jpl. That was, you know, led by a number of people there, Matt Shaw, who's you know some of those people have left. But Matt Shaw was one of the people who, you know, led this this project, and you know it was. It was pretty amazing to have them pull this off in such a short period of time.
Vikas Anant: So after we got rid of the cryo the problem was, we didn't actually have anything to test our detectors with. So you know, we made them. But the testing kind of stalled
Vikas Anant: but by June we built another one. And so this thing you know, got down sub kelvin temperatures, and we used a kind of a big cryo cooler to do this with. This is a 1 Watt GM. Cooler. So there's a lot of cooling power. It wasn't, you know, sure
Vikas Anant: how much we could scale this. So we kind of picked something that
Vikas Anant: that would work a 1. Watt cooler consumes a lot of power. So you're talking about, you know.
Vikas Anant: Roughly speaking, I think around 10 kilowatts or so.
Vikas Anant: So it's it's a bit of a beast the idea would be to try to scale this down you need 3 phase power, and and so on. To set this thing up
Vikas Anant: water cooling by the following year we had figured out how to, you know, scale this thing down. So this is now with a 10th Watt cooler.
Vikas Anant: What's nice about scaling down the power requirements of the of the crygenics
Vikas Anant: is that you know, this thing runs off 110 volts. You could have this thing in your kitchen and get down, you know, to sub kelvin temperatures in there. Which is pretty neat.
Vikas Anant: And you know we're kind of inspired by kitchen appliances that you know. Kind of wanted it to look nice as well. So it's got this brushed, you know, kind of look and now we can still flip it over and take it apart. Taking this thing apart was was, you know, the other idea was, it has to be accessible to people who aren't. You know.
Vikas Anant: I guess. Weightlifters and things like that. You know, to take this thing apart you're lifting on this this stainless steel can which might weigh, let's say, around 10 pounds or something, and that's you know that's a lot easier to do.
Vikas Anant: So so there's that the other part about Fielding. This thing is that it has to be, you know, easy to use. Software is really important. You know, people who are not cryo people by choice
Vikas Anant: don't want to deal with
Vikas Anant: you know,
Vikas Anant: just the complexities of running across that. So so you know, that's where a lot of my coding that I did during grad school and before, you know, came into play and and kind of making guis and and things like that for for people. So that that was good. Shortly after that we got our detectors to work much, much better. So we hit.
Vikas Anant: you know, higher efficiencies. Let me just run you quickly through this plot. So you got your bias current on the X axis
Vikas Anant: as you increase that, the efficiency goes up. And you see this, you know plateau. That again happens at at this 800 millikelvin sub kelvin temperatures
Vikas Anant: these are the dark counts that are around, you know, 100
Vikas Anant: counts so, and most of that comes from black body radiation. The fact that your fiber is warm. Those photons are what are going into the cryostat.
Vikas Anant: This is what a detector pulse looks like. You see this sharp rising edge slow falling edge here.
Vikas Anant: This particular detector was ready for another photon in about 50 nanoseconds or so.
Vikas Anant: and then this is the other metric for these detectors, people like, which is the timing jitter, you know, basically the spread in when that pulse comes out of the detector, you know, around about 100 picoseconds or below, seem to again be interesting. And all this is happening at 1550
Vikas Anant: nanometers, which is again a key wavelength for for people in the optics community is a lot of components that they can buy at at that telecom wavelength. Okay?
Vikas Anant: you know, a year after another interesting development the Uk government decided to invest 214 million pounds in quantum technology they were.
Vikas Anant: I think
Vikas Anant: ahead of you know some of the other governments that then followed suit
Vikas Anant: in Germany. And I mean at this point, it's a lot of different governments, and even, you know, regions and even cities that you know start to pour money into quantum
Vikas Anant: but you know, back then, this was. This was a new thing, and you know, I was then since we had the detectors, you know performing well.
Vikas Anant: I fielded a question of well, how many of these could you put in a crash? Stat, you know we're not talking about 2 or 4 like I mean. So this is. This is a picture of what it looks like in the crash. Stat, where there's 32 detectors in there. So that was quite a bit of effort to try to cram them in.
Vikas Anant: The other question as well. Can they work at different wavelengths? So we get a detector at 1310 or 8, 25, 7, 80 whatever. So so we ended up optimizing the detectors for different things. This is a similar plot like you saw before.
Vikas Anant: This is for 2 of our detectors from the same wafer you can see they, you know, they match up pretty well. That's kind of partly the magic of that material.
Vikas Anant: The other interesting thing, if you look at the
Vikas Anant: the you know the other 2 curves here. These are the system. Dark count rates at 7 around 7 80. The dark counts are extremely low. You know, you can be operating at a point where you have full efficiency. And you know.
Vikas Anant: essentially 0 dark counts. But in reality there might be like one count a minute, or something like that.
Vikas Anant: That's really exciting to people in the quantum optics community who really, you know, they care about that ratio between efficiency and dark outs.
Vikas Anant: So so that was neat, you know, by 2016. You know.
Vikas Anant: my daughter had grown up a bit more and we had worked on a small business innovation research. You know, Grant, from Darpa to build a much smaller cryo. So this is a rack. Mount cryo where everything is inside that box we have a cryo. You know the cryostat, the compressor you know.
Vikas Anant: A vacuum pump even the whole lot inside there. The thing that's not in this picture. The only thing that's not in this picture is we had temperature controllers that we didn't you know, scale down.
Vikas Anant: but that you know, one could have done that as well.
Vikas Anant: So yeah. So this, this is good. This actually worked
Vikas Anant: and then, a few years later, we figured out how to make really good detectors. So this is in 2018
Vikas Anant: where by this point, NIST had set up a calibration service. So you can send in detectors
Vikas Anant: and they will measure them. So we sent them in. And they measured one of these detectors to have an efficiency of 95 and a half percent
Vikas Anant: and this is the, you know, the confidence interval where it's between 94.9 and 96.1
Vikas Anant: so you know. So this is, this is neat. This is another. You know, part of that test where you can see it's 95%. As you increase the count rate some of those photons
Vikas Anant: arrive when the detectors are covering. So the you know, the effective efficiency goes down.
Vikas Anant: But you know. But this was a a very good way to prove to ourselves and to others that look. We know how to make good detectors.
Vikas Anant: Since then, you know this is not the record
Vikas Anant: Since then people have made detectors with, I think, close to people at NIST have made detectors close to like 98% efficiency. So so that's pretty neat. We kept improving the cryo as well. So this is a bit more like what our products look like now.
Vikas Anant: So you have this tabletop unit similar to what it is before. There's some subtle differences. But essentially the idea is is quite similar as what you saw before. And then rack mount. So people like putting these things in in racks I think, partly because of the quantum you know, technology kind of shift where they want them to look more. They don't want them to look so.
Vikas Anant: you know, like they just came out of a lab, right? They just want them to look like they belong in the data center. So okay, you can put them in a rack.
Vikas Anant: The other nice thing with transportation when you make something that that small and compact now we can transport it in a I mean, this is a military grade case, but it's a you know, not much bigger than a suitcase.
Vikas Anant: That you might check in
Vikas Anant: And and so that's how that's how we transport it. The on the sorption fridge side. We figure out how to make this thing work much, much better. So now it stays cold for, you know, over 2 days
Vikas Anant: in one shot there's a duty cycle, of course, is a couple of hours, and then you can go again for 2 days.
Vikas Anant: the other, you know. Part again that was customer driven was, well, can we fit in a lot more channels? So this is a 64 channel you know, desktop system. Where you could, you could have a lot of detectors in there.
Vikas Anant: You know.
Vikas Anant: There, again, we're when we built this thing, we figured this is actually kind of a pain to to
Vikas Anant: you know.
Vikas Anant: open up because you have to do this flipping over. And so you can imagine you got to unplug 64 fibers and 64 coax cables if you ever need to open it up so then we ended up, you know, making it in a in a rack as well. So this is what it looks like. You have the crash stat in fact, you can put all the electronics you need to operate this thing in the rack.
Vikas Anant: You know it. Ships like this, what you see on the right
Vikas Anant: and
Vikas Anant: you know, what's also nice about this is, you know, this thing comes with ramp. So you can actually, just, you know, roll it off and there's no crane involved. And even to open it up, it's it's quite simple. You don't need to be able to lift anything heavy.
Vikas Anant: This is a picture of another system that we built where it's now a a camera. So there's a an array of detectors in there.
Vikas Anant: and so this is something that is out with the customer right now, and and they're gonna be publishing results on this soon.
Vikas Anant: Since we got pretty good at making cryos, we kind of branched out. And now we're also making a cry. Stat, that has very good temperature. Stabilization turns out this is very, very useful for people working on Joseph. Injunction arrays
Vikas Anant: where they don't want to see large oscillations that the cry cooler has, so we're able to reduce it down to a couple of Milkelvin with the kind of design that we had
Vikas Anant: on the
Vikas Anant: other application side. And I guess, looking ahead. You know, we've delivered a system for that. It's gonna be used for optical com
Vikas Anant: from the Artemis 2 launch. That's gonna happen. So this is the Orion spacecraft that will launch with astronauts to go around the moon
Vikas Anant: and and that light is, gonna go down
Vikas Anant: to telescopes in New Mexico and then be fed into one of our middle class stats here.
Vikas Anant: This is a project that involves Lincoln Lab and Jpl. NASA Goddard.
Vikas Anant: You know, to to have this thing all work
Vikas Anant: and just as a comparison. So if this spacecraft were to communicate down. I found this in a paper about this mission, you know, with microwave you would only be able to downlink about 7 GB per day. With optical calm they can do 36 GB in about an hour. Window. And that's really is what's transformative about this is that you can do this.
Vikas Anant: You know, it's broadband for space. You know, I want to see videos from from space.
Vikas Anant: You know of the astronauts of when we send missions to Mars.
Vikas Anant: there's in fact, another you know
Vikas Anant: launch that has been quite successful where they've sent a spacecraft out to the asteroid belt and along the way it's been doing optical com
Vikas Anant: and so that I think they have data from where it's near Mars orbit. And it's also been
Vikas Anant: so that's the Psyche mission. You guys can look that up if you want
Vikas Anant: the other interesting development. Just last month we landed a sbir from that was funded through the Chips act.
Vikas Anant: So that is, you know, we're kind of going back to where we started, where we're now. We want to make a cryo for again for integrated circuit evaluation.
Vikas Anant: And but this time the detectors are far superior to what they were 14 years ago. We can make arrays. The group at NIST knows how to make arrays that might have a hundred 1,000 elements in there. So it's going to be far more impact than than it was before.
Vikas Anant: So that's
Rodgers RLE Lab: Just want to do a quick time check we have about.
Vikas Anant: Yes.
Rodgers RLE Lab: 15 min left in regulation time.
Vikas Anant: Pretty much done so my last you know, slide is we are hiring. We are looking for people with.
Vikas Anant: you know.
Vikas Anant: You know the relevant skills you can see on the left. and why one would want to work here. Well, la and Pasadena are, you know?
Vikas Anant: I think, the nicest places to be in in the United States. We are a small company you can have a a big impact. We have some awesome collaborators and customers, some of which some of whom are, you know, may well be in the room.
Vikas Anant: right now. We are not Vc backed. Which.
Vikas Anant: you know, I see as as more of an asset. You know, I I don't know whether Vc. Would have had the
Vikas Anant: you know, patience to to kind of see these ups and downs. But you know, that's something that since we're not Vc backed, we can kind of do.
Vikas Anant: And yeah, and this is this is what where we are right now. So that's that little girl who's now a teenager in some ways photon spot as a teenager as well. We've changed our appearance as well. So you know, the logo now looks like this compared to what it was before.
Vikas Anant: And
Vikas Anant: yeah, I think I'll I'll stop it there. So I'll take any questions. People have.
Rodgers RLE Lab: First.st Thank you so much.
Rodgers RLE Lab: Any questions from the room. It's a lot to
Rodgers RLE Lab: a lot to absorb. But any questions, yeah.
Vikas Anant: I hope this is in the spirit of what you were after. But
Rodgers RLE Lab: It's great.
Rodgers RLE Lab: I can ask one. Yeah. John has a question it might be difficult. So you have a competitor. That company is called single content.
Rodgers RLE Lab: and they told me that detector can operate at slightly higher temperature
Rodgers RLE Lab: doesn't require subcal in operation. So what do you think of other material candidates
Rodgers RLE Lab: for your future detectors.
Vikas Anant: Yeah, I mean,
Vikas Anant: that's so. They're not the only competitor. There's 5 other companies in this space. Maybe more. So
Vikas Anant: you know. I think,
Vikas Anant: there are pros and cons, obviously to what we do. There.
Vikas Anant: it's to date.
Vikas Anant: you know, the highest. I think it depends on the metrics you're really after. Okay. So the reason to run at warmer temperatures is to reduce the cost of the cryogenics mainly because it's a much simpler thing
Vikas Anant: the other. Metrics are not really improved by running at warmer temperatures.
Vikas Anant: Superconductivity is, you know, strongly, you know, relates to temperature, you get a much higher current density when you operate cold.
Vikas Anant: So that's really the reason to add colder.
Vikas Anant: I don't know what you know yields are whether they're better or worse. But you know
Vikas Anant: with
Vikas Anant: you know, materials made out of nibum nitride nibum ty nitride. It tends to be a yield thing.
Vikas Anant: yield issue
Vikas Anant: but you know they're obviously a very well driving company, and you know, and and I think they're able to make it work on our end. You know, we like the colder temperatures it gives our, you know, process a lot of latitude when we're making detectors, we can, you know, make you know we didn't make thousands of detectors to make across that with 64, right? You know, we had.
Vikas Anant: I think most of them were from one or 2 wafers. So so that was good, and then
Vikas Anant: and then on the cryogenic side the the other part that people
Vikas Anant: you know
Vikas Anant: who are cryo. People understand this, but you know, is there's wear and tear on on the cry cooler. So when you're running the cry cooler over time, you will see degradation, and it won't be at 2.5, or whatever that magic temperature is that you want to run this thing at it might go up to 2.6 or 2.7 or 2.8 right, and if you go back and look at what happens.
Vikas Anant: if you if you remember earlier in my talk where I had these waterfall plots, I can. You know what I can go all the way back there right?
Vikas Anant: So this is early on here.
Vikas Anant: If you look at this thing right, I mean, if you go up by a 10th of a Kelvin, you may start losing some of that plateau until a point where you don't have a plateau at all.
Vikas Anant: Okay, so now, your efficiency is a function of the age of your crash set.
Vikas Anant: And that's you know
Vikas Anant: people live with that trade off, of course. But
Vikas Anant: The way I've you know.
Vikas Anant: built our products is that
Vikas Anant: I want this cry Stat, to last the lifetime of a grad student or postdoc in a lab right? So if it can work for about 4 years, everyone's happy, and then, you know, you need to service it. So sorry longer answer than maybe you're asking for. But yep.
Vikas Anant: go ahead.
Vikas Anant: I hope that answer your question
Vikas Anant: right?
Rodgers RLE Lab: I had a question. I was wondering when you were trying to stuff as many detectors in your cry Stat. As possible, what kind of trade offs were there.
Vikas Anant: So you know.
Vikas Anant: from a design standpoint without
Vikas Anant: making this thing bigger. I mean, there are a lot of practical issues of you know.
Vikas Anant: just
Vikas Anant: I would say mechanical engineering side. I mean, you know, you got all these fibers to deal with. Right fibers are very annoying. You know, they break really easily.
Vikas Anant: And it's even worse when you have a fiber splice in there.
Vikas Anant: You know, that isn't protected. I mean, we would have this issue, where, if you were installing a detector, you might break 2 splices in the process. So you know you, it would take it could take a while to converge, and of course, you know, we had to to
Vikas Anant: fix that
Vikas Anant: aspect of it and kind of get more organized about how we install detectors.
Vikas Anant: But you know the the on the
Vikas Anant: cryogenics side.
Vikas Anant: I mean the-the-
Vikas Anant: there was a a limit to how many detectors you could put in there before.
Vikas Anant: You know the hold times the operating time kind of shrunk
Vikas Anant: and so 32 was about the right, it turned out, was. You know, you had all those detectors in there, you could still have about a 24 h, you know, whole time, 24 h time to actually operate them.
Vikas Anant: Which is okay.
Vikas Anant: But yeah, most of the most of the issues were, you know, mechanical, I would say.
Rodgers RLE Lab: Yeah. Yeah. But when when they're you get them in there mechanically and and but they're all at different points. They're all attached to the crystat at different points, so there must have been different. The distribution of actual temperatures attained right.
Vikas Anant: potentially yes, not something that we measured very carefully the nice thing. And actually, this plot kind of shows it if you're at this temperature, and you're off by a little bit. Things aren't changing dramatically, you know, or you say you're in this regime over here versus when you're over here where you actually see the shift. The detector itself, you know, once you're sub kelvin.
Vikas Anant: it's not as sensitive to oh, is it point 8 5? Or you know, point 7 5 or whatever it. It's okay. With, with a slight change in in kind of that base temperature.
Rodgers RLE Lab: Yeah, John has another question. At the early stage of your company. You have this monster
Rodgers RLE Lab: huge rack that you sell to that you sold to Jpl.
Rodgers RLE Lab: So that's really impressive to me. I naively thought people need to do lots of engineering
Rodgers RLE Lab: when you send something to space and and.
Vikas Anant: Oh, no, no, no! The if I misspoke, I'm sorry that thing did not go to space. That thing was on Earth. The the satellite is in space and it's it's for the downlink. So yeah.
Vikas Anant: yeah, no, no, no, that. Yeah, we I mean to right now. The detectors.
Vikas Anant: I don't think they're really space qualified. I think people have done some, you know, tests and measurements on them to make sure they can handle the radiation and that kind of stuff. But to my knowledge, I I don't think they've been flown
Vikas Anant: but I I might be wrong.
Vikas Anant: so.
Rodgers RLE Lab: Alright. We'll wrap it up there. Thanks again.
Vikas Anant: Thank you.
Rodgers RLE Lab: And thanks to everybody in the room for coming.
Rodgers RLE Lab: we'll see you next time, and because thanks again.
Vikas Anant: Yeah, thank you. Alright. Guys.