Laura Waller (UC Berkeley)

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Peter O'Toole: Hi! I'm from the University of York, and on this episode of my I'm. Joined by Laura Walter from us in California. Berkeley. Laura, how are you today?

Peter O'Toole: Well, thank you for joining me. I i'm intrigued because you're not a classic microscopist. I think It' be fair to say,

Peter O'Toole: but I So I I know you, uh from an invitation you when you were speaking, and invited to Keynote Speaker for Carl's ice. Actually, i'm talking about phase microscopy.

Peter O'Toole: How did you get into microscopy?

Laura Waller: Um. So in grad school I was working in the lab of George Barbastathis at Mit and uh. So his group at the time did a lot of um nano photonics and a little bit of microscopy. So he had worked on

Laura Waller: um holographic data storage and had some ideas for using it for microscopy. So he was doing that already. Um! And then so I was working in that sort of like the imaging side of the group, which wasn't very big at the time. Um!

Laura Waller: And then I don't exactly remember how I got into phase imaging. I think it was through this project that I was doing to try to image um image like the

Laura Waller: the like clear membrane films that you put in fuel cells, and we're trying to image the humidity within these films like in situ, while it's in the fuel cell.

Laura Waller: And we were trying to do this with optics, so it's a humidity thing. So humidity is affects density and density as refractive index. So we were trying to do refractive index mapping, and I got into phase imaging, and then I was part of the Singapore mit program um in grad school. So I spent I had to spend a couple of months a year in Singapore, and uh, I was officially part of a center for environmental sensing. Um, But Colin Shepherd was working there, and he was really fun. So I just hung out in his lab

Laura Waller: for a few months a year, and he was doing lots of phase imaging, and I think that sort of uh spurted along as well.

Peter O'Toole: So that's how That's how you got into the bio side. I presume that when you're working yeah, it's definitely through Colin. What was it like in Singapore?

Laura Waller: Hot uh Singapore was really fun. Um! It's a really cool place, because it's so unique like it's in Asia. But It's pretty Westernized. It's super clean and well regulated. I actually really liked the the whole like rules and

Laura Waller: and people following, following what you're supposed to do everywhere. Um, yeah, and we, The Singapore mit program was a great exchange program. I met a lot of great people. I'm still friends with some of the grad students from Colin Shepherd's lab that I became friends with,

Laura Waller: and I had some friends in the program from Mit, who would go over with me, and we would just have fun traveling around Asia on the weekends. Um: So yeah, it was fun.

Laura Waller: Yeah, i'm going to say travelling around Asia, not travelling around Singapore, because Singapore is pretty small. Yeah, that's right. So we did trailer in Singapore, probably the first weekend, and then branched out to other parts of Asia. We learned to Scuba, dive in Vietnam. We went to Australia on the way once or Tokyo on the way. Once

Laura Waller: we went to Malaysia,

Peter O'Toole: that's one of the Perks of

Peter O'Toole: being students and studying is the ability to travel. Do you still travel a lot, Take taking Covid time out of the the frame?

Laura Waller: Pre Covid, which was also pre kids for me. I did travel a lot for conferences and such Um! My husband's a management consultant, so he's traveling all the time, so I was kind of just like free to go whenever I wanted, and I did a lot of conferences and fun places, and traveled around and uh saw the world.

Laura Waller: I did that a lot in college as well. I also did an exchange program in undergrad at in the Uk at Cambridge University, So I really like traveling uh. And then Covid happened, and I had kids, and then, now I don't travel very much unless I have to.

Peter O'Toole: So yeah. So some people got Okay, we you you you got kids Uh, yeah, I also got Covid.

Peter O'Toole: So how are your children now? Obviously quite young.

Laura Waller: Yes. The the one-year-old was a little younger in that picture that said a birthday party. So this is this: is interesting. I've never really thought about this having children due in Covid and working.

Peter O'Toole: Yeah, I do not.

Laura Waller: I think it was a good thing. So um we, my My older son, was six months old when Covid started,

Laura Waller: and we were working from home, and it was really fun because you'd you know. You take all your meetings on Zoom and then have a ten minute break, and instead of going for coffee with my colleagues, I would just go play trains with my son. Um! I got to see him a lot have lunch with him.

Laura Waller: I think it was great to see him. Uh, okay. So we had. Uh, we have a wonderful Nanny who is taking care of him during the day, and I have friends who lost their child care, and that was not fun. Um, but we didn't lose our child care through Covid. And so

Laura Waller: it was actually really fun to just get to see the kids more. And then the second child was born during Covid. Um. And I. That was really great. I actually

Laura Waller: uh had a much better maternity leave in that I just like

Laura Waller: would sign in and join the whatever zoom calls I was supposed to be on whenever I felt like it. Um! Even when he was just like a week or two old. I was on zoom just holding him sleeping in my arms or nursing him. Um! And it was like I kind of liked it to like stay a little bit involved in work as much as I wanted to be um,

Laura Waller: while also being able to just stop and take care of my baby when I felt like it, or when I was tired I could go and sleep. I I I I remember when we had young ones I I was for so I I I stayed with my wife who

Peter O'Toole: took maternity leaf, and then went back part time not full time. In that case, I remember children actually been a very young

Peter O'Toole: been quite easy, because a lot during the working day they're asleep quite a bit. It's done. How did you say you finally get more difficult now than you did through Covid. Um

Laura Waller: no, uh, not really cause it. Well, they're still pretty young, but we we still have good child care, so I think that helps. And then

Laura Waller: uh, now it's a little bit harder because my husband's traveling a lot for work. So my night and weekends I just don't have can't really work much, because uh, I have the kids alone a lot on the on the nights. Um, So i'm really working fewer hours than I was before. But I figure

Laura Waller: It's a good opportunity. I want to see my kids grow up, and in how many years will they not even want to see me anymore. So So i'm certainly working less now, but it's fine. It's uh it's It's enough to

Laura Waller: they're way too young to start thinking when we may want shot of you way way way too young for that. Oh, my three year old already tells me to go away. Sometimes

Laura Waller: I I've got to. I've I've got to ask looking at a telescope behind you. That's right. That's telescope uh from somebody to give that to us for our wedding. Um!

Peter O'Toole: That's a pretty cool case. That's a a a night sky. So actually, anyone who's listing it to it to an astronomy telescope. Not a bird watching telescope.

Laura Waller: Right? Yeah.

Laura Waller: Um, we haven't used it much. Uh I haven't had much time to use it. Uh,

Laura Waller: so I've barely taken it out. Um, but uh, someday with my son. We also have a project now to thinking about correcting operations for large aperture imaging systems, so we might play around with it for that.

Peter O'Toole: Let's say that I say back onto the microscopy side then, and

Peter O'Toole: I I saw that you're also so obviously with with phase imaging you can do lens to phase imaging. We can do Lenses

Peter O'Toole: phase imaging as well.

Peter O'Toole: But I do. I notice you also, working with cameras as in photography, type cameras for face imaging.

Laura Waller: Yeah, so not so much for face imaging. But, like the lens less imaging like our diffuser camera, is just basically like a scattering element on a sensor like you can just put Scotch tape on a sensor. Um, and we've used that for microscopy. But it's much more simple setup when you use it for photography,

Laura Waller: because everything is in the far field. And so uh, you have simple Fourier transforms, and things are more shift, invariant system, lensless system. So yeah, we do stuff for photography and for microscopy. We also do X-ray microscopy and electron microscopy. We're pretty agnostic to the the regime of

Laura Waller: electromagnetic waves um and the size scales of things and Now we're like starting to think about things in in space telescopes so spanning the full pipeline of size scales. Oh, nice space telescope. You also say this picture. This can't be related to that. Surely this is not. This is

Laura Waller: This was something my husband really wanted to do, going on a zero gravity flight. This is zero. I think it's called Zero G, and this was his reward for a promotion that he got, and I didn't want to go. I was really scared to go. It's a plane that just sort of

Laura Waller: goes up and up and down, and you get some weightlessness for like forty forty-five seconds uh maybe like ten times over this course of the flight. And uh, I was super scared to go, and then I had a blast um. Meanwhile my husband, who's in the background there?

Laura Waller: He looks fine in that picture. He was just lying on the ground, trying not to barf the whole time. This is my extreme reading photo for it. I was trying to read it. Paper um while in zero gravity explain to you. So I've seen your website, and, as you say for for extreme reading. What

Peter O'Toole: explain? Where did this start, and what is it? What is extreme reading? And where did he start?

Laura Waller: Uh, So it was a play on. I don't know. If you remember, a long time ago there was this thing called planking uh, where you just like, straighten yourself straight as a board and take pictures in crazy places. And then we saw, like an extreme ironing thing, where people were ironing on the top of a mountain, or something like that,

Laura Waller: and my my in-law. We were visiting Germany, where my husband's from, and my in laws were making fun of me for carrying papers around everywhere we went, because I I would print out papers and carry them around, and when I got a chance to read them I would read them, and then I could throw them out after I met them, and so uh they took a picture of me

Laura Waller: reading a paper in front of the New Year's fireworks in Berlin, and that was the first one, and then I thought it was funny. So I started

Laura Waller: taking. I always had papers with me because I was always like reading them when I was traveling, and then I would just get people to take pictures of me reading them while I was in funny places. So firstly, I've got to check. This was

Peter O'Toole: jun a firework display with your in-laws you chose to do some scientific reading.

Laura Waller: Yeah. So okay, there there's a reason behind it. I We were gonna babysit the nephews

Laura Waller: that night, and so I brought a paper in case babysitting was boring. But then I happened to have it with me at New Year's at midnight during the fireworks and the phone works so boring that you got the paper out right,

Peter O'Toole: and then I just came a thing it's on my I. It became a Facebook album, and people kept giving me ideas of where I could do it do more extreme things. So you send me some picks to this. So I say, first one, I I So this where where are you with this extreme meeting? Uh, that's in Maui at the top of the the big volcano and Maui, I think it's called.

Laura Waller: That was before we did a sixteen mile hike down the volcano

Laura Waller: to count as extreme reading. Do you have to read the whole paper, or do you just get it? Um, I do read the paper usually, but not always on the spot. It just have to be a real paper. So uh, I don't always read the whole paper in the event. So you also sent me

Laura Waller: this one, which is, and Disneyland Uh: I had a conference at Disneyland, and

Peter O'Toole: I basically paid the entrance into Disneyland. Just so I could go and take this picture. Okay, So this really is extra. This Isn't: Just extreme reading. This is extreme photography of you Reading and and I had to pay the Splash Mountain people for this photo. Probably twenty bucks it. It is a very good picture for those who are listening. You got a child at the front looking very scared.

Peter O'Toole: You got two grown men with their arms in the yeah, having a whale of a time, someone in the middle who can't see quite well, but Laura is sat at the back of this, looking almost like she's lying back, folding legs, reading a paper completely non plus

Peter O'Toole: by I I pursue the form that you on going down right now.

Peter O'Toole: Yeah, this is. This is a big drop in Splash Mountain right at Disneyland.

Laura Waller: Uh yes, this yeah, it's not very wet.

Peter O'Toole: Okay? And and then it gets more extreme.

Peter O'Toole: And now you are actually reading on an elephant walk city on an elephant's knee.

Laura Waller: Uh, I don't remember this was in Africa. It was like one of the things you could do while you were there. What we'd pay is to single and elephants need that. That's an you can many people.

Peter O'Toole: And then I I think, probably the most extreme. And this is a super cool picture where this is New Zealand uh on an iceberg in New Zealand. It's one of these helicopter tours of the iceberg and New Zealand.

Peter O'Toole: It's a really beautiful place. Really cool I have a lot of photos from this location. This is probably the coolest one inside an ice cave. Yeah. So if I say so, yeah, you go. It's nice cape that you're sat in lying back, reading

Peter O'Toole: quite clearly aside to, but with images we'd like That's right. I don't remember which paper Sometimes the papers are themed to go with the location, but sometimes they're just random.

Peter O'Toole: I I I I i'm trying to think now, when you got fireworks when you got the ice cap when you've got an elephant, how you are going to them. The paper that you are reading. Yeah, I don't have. I can't remember any examples, but there are a few that were funny choices given the location.

Peter O'Toole: So i'm going to cover anyone listing to go and actually find the website, because I I have had a look at the website, and you are even at your wedding.

Laura Waller: That's right, and everyone on our wedding knew knew the joke. So it was just funny,

Laura Waller: actually. That's how my husband proposed, so I don't know if he saw the proposal one. But my husband proposed we were in front of a waterfall after a long hike,

Laura Waller: and he asked someone to take a picture of me extreme reading, and then he was proposing: Did you see him on his knee while you were reading, or did you? Then? Yeah, yeah, that's it. Like the photo is real. That photo is not um. It's not uh

Laura Waller: like staged or anything,

Laura Waller: so he's all in on it as well. I have a lot of support. I'll kind of in some teach you not reading well while she actually doing a podcast, I should be, You know I don't print out papers anymore, and that's partly why I haven't done it so much anymore, because I read everything in Pdf nowadays.

Laura Waller: So you just need to just speak the tablet to test. Yeah, yeah, it's on the phone as well. Now, it's in it as well. So it Doesn't: Yeah, doesn't feel the same to do that.

Peter O'Toole: Ah any. Anyway, we we will move over from that side of it from the

Peter O'Toole: extreme. You you you mentioned if I I i'm fascinated by the photography side, so I know it's my cost me what the image I Haven't actually seen in the papers for the photography side. What are the images of

Laura Waller: just like people and stuffed animals and stuff like that? So a lot of the lensless imaging stuff. We,

Laura Waller: you know. You just take a picture. You just go out and take a picture. A lot of it is students taking pictures of things they want to.

Peter O'Toole: So why do it? Why, why we move the lens? What's the advantage

Laura Waller: uh It's more compact and cheaper, and, in fact, uh so

Laura Waller: like lenses. My cross vp is always sold as or lenses. Imaging is always sold as like compact and cheap. But if you think about like, your iphone camera is already pretty compact and very cheap, so it's like arguable. Um! What's useful there? I think. Um.

Laura Waller: So. So we I even have a slide. That's like cute. But what's it good for? Um, Because lenses imaging um is somewhat of a parlor trick in It's like standard form. It's like cool that you can do it. But is it useful? But there's also been so many really interesting things that have come out of people trying to think about like. Okay, It's not going to replace your iphone camera, maybe, but it can be

Laura Waller: useful for all these other things, because it's different. So like, for example,

Laura Waller: um you can make really like, instead of having a really large telephoto lens that's super bulky and heavy, and a humongous volume lens.

Laura Waller: You can make everything more compact and achieve similar things. Um, or what we've used it for a lot is um exploiting compressed sensing. So this idea that, like the point in your scene doesn't get image to a point on your sensor. It gets image to a whole two d pattern. So it maps to a lot of different pixels, and that's a multiplexing effect

Laura Waller: which can be exploited to use compressed sensing. So that, like if I delete some pixels, then I would still have information about that point, because it mapped to a lot of different pixels. And so, um! You can use this instead to to leverage like three d imaging, or like

Laura Waller: higher, dimensional imaging. So you take a two d image and you reconstruct a three d scene. Because of this multiplicing property you can use compressed sensing to try to reconstruct

Laura Waller: more voxels than you measured pixels. So we've used it for a lot of compressed sensing examples for three d imaging or hyper spectral, which is also three D. Because it's xy lambda,

Laura Waller: or like ultra fast imaging with rolling shutters, which is just a neat idea of using the rolling shutters speed to get at um higher, higher

Laura Waller: frame rates effectively.

Peter O'Toole: Yeah. And then when you go to the microscopy side, obviously you have the quantitative aspects as well.

Laura Waller: Yeah. So on the microscopy side. Um, the way we've done this diffuser cam is basically Uh: so we've made a flat version. You can make it a really flat camera, a really flat microscope. And this is useful for things like. So like we've been working with

Laura Waller: uh neuroscientists at Berkeley who want to image brain activity in mice. And so like, when the neuron fires, you can have it, you have a neuron light up when it fires. This is like Opto genetics and related techniques, or now it's all about voltage sensing um. So in neuron fires and it lights up. Then it's. So we're all about like trying to track which neurons lit up, at which time and this happens fast, like millisecond time scales,

Laura Waller: and it's in three d. So you've got these points in three D. So you don't have time, or like

Laura Waller: the you, you can't really like point. Scan very easily across like huge volumes with high resolution, and so these, like like diffuser. Cam is a great way to get single shot. Three d imaging, if you just want to like,

Laura Waller: detect and localize some points, and then it's compact. Right? So it's a flat cam that you can just mount on the head of these mice, and they could run around without um without having a huge microscope attached, which also means the need for anesthetics is reduced as well.

Laura Waller: Um, yeah. So you, if you want, can do it on behaving my set are running around. Then. Yeah, there's they don't need to be anesthetized, and then you can do all kinds of different experiments. So, like our collaborative study, say the cortex which controls a lot of like motor and visual um stuff. And so you can.

Laura Waller: You can like, see what happens in the brain as you feed them visual cues, or as you feed them like motor cues, like running around on a ball or something like that.

Peter O'Toole: Oh, no, I was gonna say this is mind blowing stuff, But actually, I haven't just talked about my size. Not the best turn to use it. It is highly complex stuff from from the maths perspective, and in just thinking about how to actually execute

Peter O'Toole: the application is not trivial, or you you make it sound easy. You make it sound like the cameras really basic. And actually it's It's still clever to get it to do what it's going to do. But then the application side, How on? How important are the collaborations to develop in your research in different directions?

Laura Waller: Yeah, it's pretty essential in most of what we do. Um. And I would say like We go about research in a little bit different way than than like biologists or nih would expect. They like hypothesis-driven research like Here's a problem. I'm going to be an engineer and figure out how to solve it, whereas we're like,

Laura Waller: Oh, cool. I can put sketch, tape on a sensor and make this camera. What is it good for? And then we go looking for like customers? Um! And and that way it works too. So. But it means that we have to do a lot more like

Laura Waller: like sort of like.

Laura Waller: What's the like

Laura Waller: beating the pavement to try to find the right customers. So I do a lot of talking to people trying to find collaborators who can use the kind of stuff we're doing, and then maybe we modify it or change the design or come up with new ideas based on what their particular application space problems are. But yeah, particularly like all the neuroscience work we do has to be in collaboration. We don't have mice in our lab. We don't know anything much about

Laura Waller: actual neuroscience. So um, that's a collaboration, and it's a wonderful collaboration. And then a lot of the biology work we do, even like phase imaging and cell imaging. Um is in collaboration with with people who want to use the devices and talking to them and understanding

Laura Waller: what they want from their imaging systems.

Laura Waller: But I really enjoy working with other people. So it's fun.

Peter O'Toole: How easy is it? How How easy do they find grasping the concept of what you're talking about to start with

Peter O'Toole: when you, when you

Laura Waller: I think it's fairly easy to explain that we can take these pictures, and they contain information about three D. Or something, and then

Laura Waller: then people can just sort of think of it as magic. How you reconstruct the image which in some cases, if you, if you use black box, neural networks, it kind of is magic, so it's science, not magic, so sorry. Look! Are they skeptical of

Peter O'Toole: You'd be telling me this, and skepticism of the

Laura Waller: I don't think so. No,

Laura Waller: I think most people are. If you show them

Laura Waller: something related, they can believe that it will work for their application.

Peter O'Toole: So oh, i'd say, this is the whole technology. I I know

Peter O'Toole: Holography's been around for some time, but this is a very rich period. It's it's it's. It's a cool time.

Peter O'Toole: It's enabling you and others to do so much more than just couldn't be done before.

Peter O'Toole: So when you were going to university, you could never have even known

Peter O'Toole: that these sort of things existed. So i'm gonna take you back now to Maybe when you were ten, eleven, twelve, you remember what the first job is that you actually wanted to be when you were young.

Laura Waller: Uh, I think when I was really little, I think I wanted to be a lawyer, but i'm not totally sure.

Laura Waller: Don't remember that. Well,

Laura Waller: I have no idea this was like, you know. Everyone's always asking, What do you want to be when you grew up? And I think that was my standard. Answer.

Laura Waller: But I don't know why, because I didn't know any lawyers, and so

Peter O'Toole: I don't know why I would have wanted to be that. I probably saw a Tv show or something. And what what moved you into the electronic engineering you studied?

Laura Waller: Yeah. So in high school I was doing lots of things, and I was really excited about lots of topics. Um, My dad was a computer programmer, but he was really like an electronics tinker. So he had

Laura Waller: our basement was. He was a hoarder, and our basement was like an electronics quarter lab. That was just like people would bring him broken Tvs and stuff. And this is back in the day when Tvs were simple enough that somebody at home could actually fix one.

Laura Waller: And so I spent a lot of

Laura Waller: like time with my dad fixing cars, fixing Tvs playing around with electronics. Um, And I really like that. So when I finished high school, I remember I was deciding between going into going to University for English or engineering electrical engineering.

Laura Waller: Yeah, I couldn't decide. I didn't really know the difference. I don't remember. I think I just decided I like to engineering better. And then my uncle had gone to Mit, and I had seen like a a show about

Laura Waller: the the robot competition there. There was like a Lego robot competition at Mit, and I thought that seemed like a really cool place, full of only engineers

Laura Waller: that like to do fun things like build robots. And so I just really wanted to go to Mit, and I did um against my parents wishes because it was much more expensive for them than some of the Canadian universities that I could have went to. But he said, You will,

Laura Waller: right? Yeah. So it was. It was a wonderful experience, and i'm glad that I chose that. I think sometimes

Laura Waller: that if you can afford something, it's worth it to pay more for what you really want, instead of settling

Peter O'Toole: so to us. That's where you

Peter O'Toole: hey? How you fell into engineering. But I yes, I know you an engineer, but so much is around the maths

Peter O'Toole: uh of the problems of it. So

Peter O'Toole: what would you

Laura Waller: uh definitely engineer? So um in fact, I say, i'm not that good at math uh, I'm. I I like the engineering piece of it. I like the creative ideas part of engineering. Um and

Laura Waller: um. I also like the technical part of it. Uh, but especially after being an advisor for so long, and I don't get to like, write code myself, or do the math myself as much. Um, I definitely and to identify more as like the engineer, I like thinking about problem solving problems, thinking of new ideas.

Peter O'Toole: It's the obviously the computer science side

Peter O'Toole: is is a big component. So how do I get the lab? Do you have? How many, How many staff Phd. Posts do you have with that?

Laura Waller: Um. So now it's about twelve or thirteen uh. We just had eight students graduate in the spring, which is uh crazy turnover, but i'm not so. My lab was over twenty people, and it was like too much. I can't keep up with everyone, and

Laura Waller: I can't uh like, keep on top of what everyone's doing very well. And so then people were working on things that I didn't fully understand, and I don't like that. So. Um, I just trying to make the group a little smaller, so I can manage it better.

Laura Waller: Uh, no, they're all over the place. So people in my group come from backgrounds in signal processing machine, learning, optics, physics uh bioengineering.

Laura Waller: We have a really broad spread, and I think that's a huge benefit. In fact, that's why I want to keep the group big enough to keep a good spread of skill, sets and interests and topics in the group, and I think that the Enterprise interdisciplinariness,

Laura Waller: um is really great for the group. I think everyone learns a little bit of the other parts that they don't know. So when students come in with a really strong background and optics, but not in the machine learning algorithm, side of things. Then they'll I'll like, make them take classes and

Laura Waller: in algorithms or signal processing so that they can sort of like catch up in that space. And when people come in like pure signal processing algorithms people, they have to do some experimental stuff, so that they can learn some optics as well, because that's really the heart of computational imaging is that

Laura Waller: you have, like the same person, designing both the optics and the algorithms, and not like one for each, but the same person doing both. And so obviously, people are gonna have some strengths in one versus the other, but I think it's really valuable for um for people to understand both sides of it, even if it's sort of disparate from what their background was,

Peter O'Toole: and just listening to all the different backgrounds. There was no hardcore biologist there, life scientist,

Peter O'Toole: so two

Peter O'Toole: carrying on a little bit. It's not just phase imaging you also involved with super

Peter O'Toole: microscopy as well. So what are you doing in that area?

Laura Waller: Um: Yeah. So well, that came from uh, we started doing this for your technography, which is

Laura Waller: phase retrieval plus synthetic aperture to get super resolution. So you end up with really large space down with product meaning, like lots of pixels resolved like up to a giga pixel, resolved

Laura Waller: just by coding your illumination. Light um. It's conceptually quite a bit like structured illumination which is a super resolution method. And we're doing some structure illumination stuff.

Laura Waller: We have a cool project doing um it's like fixed speckle structure illumination, and your samples like moving underneath it. And you just use the motion of the sample to do this. Spec: Speckle structured illumination for super resolution. Um, So that's you can do that with fluorescence, microscope, or or like. As a coherent method, so we do both coherent methods and

Laura Waller: fluorescence. Incoherent methods, and, in fact, like one of our specialties is, is knowing how to model partial coherence, so that you can sort of have

Peter O'Toole: the whole spectrum of coherent to incoherent,

Laura Waller: so it's not often on stomped, but actually that so? So the fluorescent stuff we do a lot of it. So it started out from this diffuser cam ideas, which is all. Um, Everything is linear in intensity. So it's based doesn't really matter other than There's a phase mask in there.

Laura Waller: Um. But you measure intensities and you solve based on intensities. So uh,

Laura Waller: yeah, so that didn't really have much to do with face. So a lot of the fluoresce the d fluorescence imaging doesn't need phase. But actually, i'm really excited about some stuff right now, with like combining

Laura Waller: three D phase imaging with three D fluorescence imaging because the three D phase map is basically your d refractive index map, which is the scattering potential of the sample. And so you can digitally remove all scattering. If you can measure three d refractive index accurately across the whole sample,

Peter O'Toole: which is hard because it's a lot to measure. Uh, yeah, I I was just saying I can see exactly where it's going, but it's the maths to get it right. And the

Laura Waller: yeah, and like writing out math for the forward model is not so hard it's the inverse problem has exponentially more degrees of freedom. As you scatter deeper and deeper into the sample. And so that's the hard part really Um. And I think that's where, like a lot of these machine learning methods have been super valuable because they can,

Laura Waller: they can approximately or even exactly solve, really high, dimensional nonlinear non convex optimization problems, which is exactly what this kind of thing is.

Peter O'Toole: Okay, it's about. I'm going to move. I I get off the the the the detail bits because i'm getting too geeky on this. And yeah, I want to know more. I'm going to ask now a a different question.

Peter O'Toole: You're still really young, but you must have a favorite publication that you've either author or co-authors uh is your favorite publication, for whatever reason.

Laura Waller: Probably I I hate to say, because then i'm like insulting the people who are on other papers.

Laura Waller: I don't know i'll let you go to the

Laura Waller: Maybe i'll just go back really far of the the favorite paper to write, or the favorite paper that we came up with was in not necessarily the most useful, or, like

Laura Waller: the best technique was Um, when I was in grad school, and we figured out a way to use chromatic aberrations to get phase images. And it was really cool, because you could just use a bad microscope objective

Laura Waller: and take a color image and then reconstruct phase from it. And it was just like single shot phase imaging it was using like

Laura Waller: It's like It's not a bug. It's a feature type approach which I really love, and it worked really well. It was like one of these examples of a project that, like I just tried it for fun, and it worked the first time, which was actually like not a blessing, because then, when I tried to replicate it later, somewhere else, it didn't work, and I didn't know why, because I didn't understand the system very well, because it had just worked the first time I did it. Um! But it was really fun. And uh, when it worked was when I was working

Laura Waller: with some folks at Boston micro machines in Boston. They make memories for adaptive optics, and they're a really fun group of people, and I was using one of their mirrors as my like phase object, and like this thing just worked, and I was able to map out the surface shape of their mirror really accurately from a a bad microscope Objective?

Laura Waller: Uh, and they were really excited about it, and I was really excited about it. We were all just like I can't believe this work. This is really cool. So that was just fun in the like

Laura Waller: seeing a new idea come to fruition and

Laura Waller: be useful quickly. And then the paper was fun to write because it was like, Guess what aberrations can be good, and I just love that kind of like opportunistic imaging approach to things

Peter O'Toole: your career to date. What has been your favorite period of time?

Laura Waller: Oh, um!

Laura Waller: Definitely, like a few years into my faculty, job. So like once my lab was up and running, and I had equipment Then I had, like all these awesome students working on all these ideas that i'd been thinking about for a long time, and like they were

Laura Waller: doing stuff like when they started doing stuff on their own. The first couple of years is like all investment. You're just teaching them stuff and getting things started. And then when they start like doing things on their own, and coming up with their own ideas and getting really cool results without you. That was just really exciting. And I had such a great great group of people, and we were like having so much fun

Laura Waller: discussing ideas, and uh, and getting everything going, and it was just like a really fun, creative time. So

Peter O'Toole: so you have all that. It is quite interesting. You said that time investment is. Get them up and running, and you say it to give to your expertise to enable them to progress what you want to progress forward with, and then they become self sustaining. They they! They become starting up by themselves. They can move forward,

Peter O'Toole: we such a high flux. So you just had that big turnover uh of of it going.

Peter O'Toole: So you have to put so much time investment in yourself now, or is there enough of a knowledge within the team that can keep to feeling. So So they now doing a lot of that teaching.

Laura Waller: Yeah. So that's the beauty of once your lab gets going. Then the more senior people can teach the more junior people and get them going. Yeah. So we still have some people that are like helping the new people start. I'm. Also teaching a grad seminar on computational imaging this semester, which is super helpful, so like the new students can take that, and get a great like

Laura Waller: intro intro to all the papers you're supposed to read, and all the like main ideas of the field. Um. So that's super helpful. But yeah, I am spending more time, I think, with students this this year because I have new people, and there's less older people to guide them

Peter O'Toole: how close, What's the longest period of time? You've had a member of your team.

Laura Waller: Oh, I don't know, because I have had. I've had a couple of grad students who started as undergrads like started like software year and undergrad or so. So we're probably around eight years or so.

Laura Waller: So. I'm. Still with you at the moment.

Laura Waller: Yeah. Well,

Peter O'Toole: the one I'm thinking of just graduated. But I have two more that just are halfway part way through a Phd. After working as undergrads for a couple of years. So and as you, I must be daunting to lose. So we've been there for eight years. It's it's good to see them fly

Laura Waller: right. It's It's just when you want to keep them. The most is when they want to leave

Peter O'Toole: it's, I guess, for that's my career Postdocs kind of just to keep one or two to keep that legacy to keep that knowledge base to go. It can be really useful. So we've asked about the best size favorite publication. What about uh, the most challenging time? Most difficult time you've had in your career?

Laura Waller: Uh?

Laura Waller: Good question. I'm not really sure, I guess like probably like now, or until recently, like I found having kids such a bomb on your time, so sucking all your time away. And So

Laura Waller: uh, I found that really hard in terms of like my career of like trying to balance.

Laura Waller: Should I go to this conference, or should I stay home with my kids. Should I like when i'm on like my maternity leave was very wishy, was she? That was like sort of like, Do whatever you want. And so, you know, like, should I like be enjoying this time with my kids, and just stop doing work for a long time, or should I

should I like, do as much as I chose the option of like

Laura Waller: prioritize my kids for a couple of months when they were born, but also be If i'm available, then do stuff for work and try to keep up with my students. So i'm not, you know, ruining their lives by not filling in forms and such. Um! But I found I. I really find that like balancing of work, Life, when you have kids, is really hard. Um,

Laura Waller: and all the all of the uh.

Laura Waller: How do I say it? Like all of the gendered crap that comes with having kids and being an academia, I find extremely frustrating, just like a a lot of like


Laura Waller: things that that uh are very gendered that really bother me, and I I waste my time thinking and complaining about them,

Peter O'Toole: so I I presume it's got more challenging now that you are back at work.

Laura Waller: Yeah, although I have also been appreciating going back to campus um to the office is sort of like really like. Getting out of the house is a real escape from from all the domestic things, and you can focus a little bit better sometimes, but it's also really hard to like. You know. You have to be home at a certain time. You can't start. You can't just wake up early and do something so easily. So uh,

Laura Waller: yeah, that's been harder to like. Have to work within a more restrict time, Frame.

Peter O'Toole: I'm gonna throw some quick fire questions at you next. First one is Pc. Or Mac Pc. But it has an apple sticker on it, so

Peter O'Toole: i'm going to stop the quick, Violet. Why is he got an apple stick here on your Pc. Because my husband has the same one, and I need to be able to distinguish them of all the stickers in the world. You chose it. Yeah, I like my iphone. So I still like apple. Okay. So Pc. Or Mac

Peter O'Toole: Pc. Mcdonald's or Bagger King

Laura Waller: Disgusting both.

Peter O'Toole: Okay. So if you get a takeaway, what would you go for actually in in Europe, Mcdonald's is pretty decent. Maybe the Nick cafe is actually not bad. Sorry? What was the next question? I take away you right to actually uh the the cafe is actually not too bad at all. Uh, if you to have a take away of any sort, what would you choose

Peter O'Toole: the takeaway uh take home uh fast food?

Laura Waller: Oh, um,

Peter O'Toole: okay

Peter O'Toole: uh

Peter O'Toole: lens or lenses

Laura Waller: uh lenses, because it's more fun.

Laura Waller: Oh, both. I have a three year old. I know the answer. You can. The answer to an or question can be both

Laura Waller: coffee for sure.

Peter O'Toole: Long Go short.

Peter O'Toole: What do you

Laura Waller: uh one

Laura Waller: white

Laura Waller: uh chocolate or cheese? Oh, chocolate for sure! Milk or dark

Laura Waller: um milk,

Peter O'Toole: milk chocolate in America.

Laura Waller: Oh, yeah, I like sugar.

Peter O'Toole: Uh what? What is your favorite food?

Laura Waller: Oh, my favorite food

Laura Waller: uh ice cream,

Peter O'Toole: Great choice,

Laura Waller: like Ravioli or some pasta

Peter O'Toole: converse to that. What will be the worst thing that they can put in front of me?

Laura Waller: Oh, seafood!

Laura Waller: And then I remember when I was interviewing at Berkeley. They take me. They took me to the like Seafood restaurant in town, and it's the only thing that I don't eat is seafood,

Peter O'Toole: and it was fine. They also had other food, so it was fine. But it was funny story I I've been to a conference, and I I've got to be very careful what I say, because i'd probably be listening to who and we went out, and it was to an island, and it was. It was shellfish, only

Peter O'Toole: two very thin slice of red,

Peter O'Toole: and at a conference dinner with on the free drink

Laura Waller: there was only two slices of the that I could eat.

Peter O'Toole: Yeah, I i'm not I. I I did do some not to. But the rest of the crafts streams everything else.

Laura Waller: What about me? Love me because I've always getting more caution, size

Peter O'Toole: or um. Sometimes, in like in Singapore, I would often go to restaurants and say, like, is there seafood in that, and they would say, No, just shrimp. Yeah, yeah, It's one of the ones that struggle most with. I I can do some fish. But anyway,

Peter O'Toole: good example of a good thing. Are you an early bird or a night out?

Laura Waller: Uh definitely an early bird? That's because you're younger. Wakes up at five in the morning. No, I've always been a early bird. I've always woken up early and go to bed early. I sleep a lot, but I do it like nine to five, usually.

Peter O'Toole: Okay. And I know this is gonna be a dark question in light of the extreme reading book or Tv.

Laura Waller: Uh Oh, I don't really read books, though I I do read journal papers. But um, yeah, we don't have a Tv.

Laura Waller: We just have like that fix on our ipad projector. Okay. So if you're into Netflix, what's your Netflix vice versa, the the the worst. It's not Netflix, but I watch dateline, which is everyone makes fun of me for. But it's it's relaxing. It's a nice like background. Show.

Laura Waller: Well, it's dateline for it's an American. It's not news, but it's about like murder. It's like real life. Murders so like how they solve the murder of some person who killed their wife, or something like that.

Peter O'Toole: That's what my husband says. He's always making fun of me. Um! But I don't know why I like it. I just do what's your favorite film?

Laura Waller: Um! Oh, the classic we used to. We didn't have a Tv growing up, but we were allowed to watch like we had a Vcr. And we would watch the sound of music over and over and over again. Um! And that was one of my live streams. As I went to all the locations of sound of music. While I was in Austria.

Laura Waller: I was traveling with a friend who had never seen the movie, and he was just annoyed because I was like, Oh, my gosh! That's the gone. That's the pergola that they danced under.

Laura Waller: We traveled around in Salzburg and solve the sites. So you didn't watch Tv, But you had a Vcr. And your dad fixed Tv for everyone else. Yeah, yeah, I mean, we didn't have cable. So like we had a Tv, but no content to other than somebody just tapes,

Peter O'Toole: and it's it's It's It's it's on that to be been to you of all the places in the world you've been to. What's your favorite country.

Laura Waller: Oh, that's nice.

Laura Waller: I think my favorite place is Hawaii. I just love going there. It's so. It's always beautiful where there's always great. There's lots to do

Peter O'Toole: so. You can't Busy Holly are in when she's you'll finish five. What about you have a favorite Christmas bill

Peter O'Toole: Christmas film um miracle on Thirty-four Street? I I it'll be interesting to see what that ons in a few years when your children start watching Christmas. What about what I can music you into?


Laura Waller: I still listen to the music that I listen to in college. So in college I listen to like Whatever was

Laura Waller: it was hit back then. But then, but then I never really like came with the times forward. So my ipod is still

Laura Waller: um

Laura Waller: things like, no doubt, and

Laura Waller: Gwen Stefani, and what else I don't even know what else like like you two. My, we've taught my my three year old. He can sing the entirety of rocket man uh, and we listen to a lot of Beatles, so his name is Jude, like the Hey Jude Angels song, and

Laura Waller: so he listens to a lot of Beatles, and i'm starting to get into that

Peter O'Toole: ninety, six, ninety, nine, mid ninety s for that. A lot of that music.

Peter O'Toole: I was born in eighty-one so when I was a teenager in the nineties

Peter O'Toole: just to thinking about. I I find it really good. Actually, I Music takes you back to particular places, so things like, no doubt I know where I was listening to it. So it places the time and the date and it it No, that's probably high school. I just can't think of. Yeah,

Laura Waller: yeah, I I a Scottish holiday for me. Okay. Now, what I listen to is my son listens to the As for the Beatles all the time, or it beetles or cocoa melon. So coco melon is like really annoying kids songs.

Peter O'Toole: At least the Beatles are so that that that's that the beat was good. No, it's not so bad also even good. Okay. So I asked you about your baby place. So Hawaii, I've asked you what you wanted to be when you were young. What you are today. We know where you want today, and how you got there.

Peter O'Toole: If you could do any job in the future, even if it was just for a day or a week or a year. What job would you like to sample?

Laura Waller: Oh, that's a great question.

Laura Waller: Uh,

Peter O'Toole: i'll give you a couple if you can't make a decision on one. Yeah, give me some choices. Yeah, you can. You don't need to. I so many jobs out there. But you know, sometimes you look at the I'd love to know what it's like to work in that environment for a short period whether I could hack it in that environment, or how much fun it would really be to be in that environment.

Laura Waller: Yeah,

Laura Waller: yeah, maybe like uh,

Laura Waller: like being in movies would be cool to see how they're made,

Laura Waller: or

Laura Waller: uh, I don't know

Peter O'Toole: that's a good answer,

Laura Waller: I think.

Laura Waller: Yeah, sure. Or maybe like, yeah, like working in like seeing how restaurants are run or something would be fun. Um,

Laura Waller: Or maybe like,

Laura Waller: yeah, like flying planes, or like,


Laura Waller: something like fun, like running a roller coaster or something.

Peter O'Toole: That's the responsibility of flying the plane that'd be pretty scary. I think that that's the I don't think i'd want to do that just for a day, though right because you wouldn't have the training. Yeah, But you can issue me, get, get, get a feel for it. I think the acting is quite. I I like the acting answer. That's quite good. And the restaurant Yeah, Can you hack it? Yeah, it's quite intense,

Peter O'Toole: you know. Could you get those skills to be that so called in balance? He wouldn't share it at you. You know

Laura Waller: how they organize everything. I'm always amazed to logistics Uh, run smoothly, or maybe we should do that. And then, when our labs like it's, yeah, we're doing, stay, go

Peter O'Toole: uh

Peter O'Toole: we've been on. Have you ha! Who have been your inspirations in your life.

Laura Waller: Oh, like general inspirations, I have a thing that I don't like to idealize people. I don't think It's good for anybody to like, you know. Like to to idolize Einstein as like the genius, and everything he did was perfect because he was the world's genius. I think it's better to

Laura Waller: take piece different pieces from different people, so like, maybe like scientifically, Einstein is wonderful. Um, or like I always like Tesla because he was uh inventing all of this stuff and and and uh fighting on like electricity standards. And I just thought he was an interesting character. Um,

Laura Waller: but that's like scientifically. And then, like, uh, I have like my some of my family, like I have some aunts that I really respect like morally, or like thinking about uh being a good person type.

Laura Waller: Uh, is it so like different people that I might, that I might respect there

Laura Waller: and then, like my mentors have certainly been inspiring scientifically. Uh,

Laura Waller: I

Laura Waller: I worked with George Barbastathis in grad school, and then I did a post up with Jason Fleischer at Princeton, and both of them were great advisors uh in different ways, and it was really it was really awesome to like to see all the the good pieces of how they run labs and try to pick up on those um. And then, when I started my faculty job, I had a lot of senior colleagues who helped me get started, or like

Laura Waller: I like, admired the way they ran their labs and tried to copy it. I had a a Mentor Andy new writer Who was He was just. He was officially retired from Berkeley, but he really just like spent a lot of time helping me get started, and was like such a good mentor, and the wonderful example of uh, I think,

Laura Waller: like being both. He was like the king of lithography, and everybody knew him in lithography, and he was very successful in that in his scientific space. But he was like the nicest person ever, and would like

Laura Waller: like. He brought me a swifter because he thought my floor. I was complaining about my floor, needing, sweeping, and just sort of like great example of a humble, nice, wonderful person, who is also very successful scientifically, and that I think that

Laura Waller: there's a few examples of that in in my senior colleagues that have been really like inspiring to me to try to

Laura Waller: uh, be as good as you can,

Laura Waller: and be be good at science, and be good at a good person.

Peter O'Toole: I should just take him out from that moment. Uh, I have

Peter O'Toole: uh, what you like as a supervisor.

Laura Waller: What am I like? Yeah. Are you a lot of freedom, or you someone who micro manages or in the middle. What would you say you? I think i'm super fun. Um, no. And so sort of

Laura Waller: I I think, like my personality is in the middle that, like when I started I was more. I spend a lot of time with, so I don't micro manage ever so I. People would say they have lots of freedom, but the more time I spend with them, the more I can influence what they're doing. So when I have a smaller group. I have, I think, more influence on. Like

Laura Waller: people are working on things more that are like what I wanted them to work on, but not because I forced them to more that I convinced them to um. And when my group was bigger I was just like two hands off that I didn't even know what some people were working on properly, or like wasn't keeping up with it. And so what I want to be is somewhere in the middle, where, like you know, new students get lots of attention, and I can influence what they're working on and like, you know, be really close to what they're working on, and then, like as they get

Laura Waller: more senior, they should be able to be more independent, but also still have a chance to like talk to me. I didn't appreciate things, so I would say like more on the hands off style,

Laura Waller: but trying to be involved. I want to be hands off, but it really involved, which is, would be the ideal. And I'm. Trying to get my group to a size that I can do that

Peter O'Toole: adequately. We are coming down to the hour. But I'm going to ask you, what do you see is the biggest limiting factors at the moment that limits research and the speed of research,

Laura Waller: and for me it's time I run out of time. I don't have time to do everything I would like uh, I do think, like sciences and research have lots of outdated ways of doing things like the Peer Review system is kind of

Laura Waller: silly. There's a lot of things that could be fixed there. Um, but it's going to be a lot of work to do that, and what we're doing has reasons why we do it.

Laura Waller: Uh, but I think people being competitive is a really big problem, and I don't like that uh this, like holding your ideas, scientific ideas, secrets like sciences for the world it's to be shared. It's to make the world better. And I think

Laura Waller: secret secretiveness and competitiveness and science is really dangerous and really bad for science, and if we would all just collaborate instead of competing, we could probably do a lot more better science faster.

Peter O'Toole: No, I I think that's a really good point. I I I I I I agree actually fully with that.

Peter O'Toole: I can understand why competition is there. I I see I can understand why people are compared to you.

Laura Waller: I think it's a shame where, if someone else is working by coincidence on something very similar or the same, you

Laura Waller: would it not actually help if they just joined up. And my group has done this a few times, actually, uh with other groups, and it's been very fruitful, because each group has a different take on it. Um:

Laura Waller: yeah. And the other problem that I worry a lot about is diversity that diversity and inclusion. So

Laura Waller: um,

Laura Waller: particularly in like optical physics. We are not

Laura Waller: very good at it, and we need to.

Laura Waller: We need to do better and do more. And we need,

Laura Waller: I think, in particular we need everyone on board. Um, and that I worry about like all the backlash to diversity efforts that's really dangerous for science.

Laura Waller: Yeah, my group is, I think it's about half women, and we have um some underrepresented minorities not maybe not fully represented, and we have some first generation college students. We have a good mix of different

Laura Waller: different cultures and and different uh backgrounds. So

Laura Waller: I think it's great that my group is like that. And uh, I mean, I still just choose the best people. I just have A. I think I have a a better chance to get some of the best people who are diverse because we have a great culture around that. So,

Laura Waller: um, I I really worry that science is missing out on a lot of really awesome people because they were not making them feel welcome enough.

Peter O'Toole: Yeah. And I think, maybe uh,

Peter O'Toole: yeah,

Peter O'Toole: thought processes, that there's one thing being well educated, this is another one having freedom of thought and being able to think radically. And I think right on that side that people can bring very radical, new, innovative thinking.

Laura Waller: Yeah, there's a lot of research. There's a lot of research that more diverse groups come up with better ideas and and work better together. And so there's there's lots of like reasons why why we should be more more like cognizant of of keeping a diverse group of people. So, as we come up to the hour

Peter O'Toole: I have to. I have to. I haven't asked you about what other hobbies you have outside of your children and extreme meeting. So what hobbies do you two to relax.

Peter O'Toole: Maybe you don't get much time to do them at the moment, but maybe you do so while your favorite hobbies.

Laura Waller: Yeah. With little kids, it's all gone. They don't have time to relax ever. Um, but actually they're pretty fun. So uh we like to take them to the Zoo, and we've been to Disneyland already, for uh,

Laura Waller: we go to like the Roller Coaster Park around here six flags um for fun. But before kids I had lots of hobbies in. Uh, I did a lot of hiking, and I still like hiking. Sometimes I used to play soccer. I played soccer in college in high school. Um, and I played for a while as in the Delta as well.

Laura Waller: Um, I mean. So you're in the Boston football team.

Laura Waller: Yeah. So I was on the Mit Works soccer team. Yes, and at Cambridge I played soccer as well on my exchange program. Year. Um,

Laura Waller: Yeah. So uh bay area is so wonderful for hiking, So that's always been a big one. I used to travel more. Um, I like traveling uh seeing new places.

Laura Waller: Um! What other hobbies

Laura Waller: uh not really much else. I hang out with my friends.

Laura Waller: That's right. Yeah, and certainly like I love my work. And so some of my hobbies were like

Laura Waller: building silly optics things or playing with optics, toys, and Demos. You can see some of that on my website, and that

Laura Waller: Uh-huh.

Laura Waller: I Think It's called optics fun or something.

Peter O'Toole: Yeah, yes, I I know I have seen this with different illusions and other bits, and on that uh, we are up to the hour. So I would just get just just one final final question. If you'll gam arch or basement whatever you have, do you have a load of just electronic dumped gear in there.

Laura Waller: No; So one of the side effects of having a porter as a parent is. I am extremely clean, and I like to. I love to get rid of stuff, and my house is very neat and tidy, and we only have things that we use.

Peter O'Toole: Okay, So, Laura, thank you so much for joining me today. Everyone who's listening to my possibly state. Thank you for listening. Please, Don't, forget to subscribe, and you've heard lots of different people mentioned throughout this podcast. But, Laura, thank you so much. Keep on doing the great work

Laura Waller: after this. Stay on because I've got lots of questions. So Laura, thank you.

Peter O'Toole: Thank you very much, Laura.

Laura Waller (UC Berkeley)