Grad Student Q&A: Isabelle Tigges-Green

By Wendy Plump
Wednesday, Feb. 16, 2022

Something as prosaic as a love of pasta may have put Isabelle Tigges-Green on the road to chemistry. As a child, she learned that if you add salt to water, it will boil at a higher temperature. She wanted to know why, but could not get a satisfactory answer—until she took physical chemistry at the University of Wisconsin-Madison. It occurred to her then that many such pressing questions could be resolved with chemistry. Today, Tigges-Green is a second-year jointly advised by Gregory Scholes and Julia Mikhailova, and an NSF Graduate Research Fellow. Here, Tigges-Green gives her perspective on life as a Princeton Chemistry grad student.

WHAT DREW YOU TO CHEMISTRY?

Chemistry – well, I developed a love for it. When I started undergrad, I really struggled in general chemistry and calculus. However, my GenChem professor offered the class a tour of his lab at the end of the semester and that really opened my eyes to the possibilities. I decided, first, to prove to myself that I could learn chemistry; then, I asked my first chemistry professor (Professor Marty Zanni) if I could join his research group. I thought, if I can figure out whether I like physical chemistry, then I will figure out how to make math work. Well, I’m still here in physical chemistry. I think the first thing is starting to get comfortable with feeling like you know absolutely nothing, being totally lost. And then you have to be willing to just ask question after question.

Second-year graduate student Isabelle Tigges-Green is jointly advised by faculty from the Department of Chemistry and Mechanical/Aerospace Engineering, and thinks her research in high harmonic generation is “fun.” Photo by C. Todd Reichart
Second-year graduate student Isabelle Tigges-Green is jointly advised by faculty from the Department of Chemistry and Mechanical/Aerospace Engineering, and finds her research in high harmonic generation “fun.”
Photo by C. Todd Reichart

WHY PRINCETON CHEMISTRY?

I was really interested in Professor Yang’s group and Professor Scholes’ group, and also the joint Ph.D. program that Princeton offers with materials science and chemistry. That program reassured me that Princeton would be very open to collaboration across multiple disciplines. And Professor Schoop–that was another fantastic group I was very interested in. There were three professors in the department whose groups were quite appealing to me, and I really only wanted to go to a place where there was that much that interested me. If you’re interested in several groups at one university, that’s a good fit. 

SO, YOU’RE ADVISED ACROSS TWO DEPARTMENTS? 

I came up with this idea and said, hey I would like to do this and I presented it to these two P.I.s. We met, they hashed it out, and that’s how I ended up being with both Professor Scholes and Professor Mikhailova in Mechanical and Aerospace Engineering. Also, I went to some other students who had a joint set-up and asked them, what’s it like? There are subtleties in each department that you should know about, and it’s good to get impressions from people who were already doing what I wanted to do. 

WHAT ARE YOU WORKING ON?

My project is high harmonic generation, specifically in condensed matter. So at the moment, we are going to benchmark our system just to make sure that it works, to make sure that we can see these harmonics. Then we will move on to more novel materials and try to make harmonics with those. We’re hoping to engineer a new, more efficient source for extreme ultraviolet light. Most lasers on people’s tabletops are going to be something like 800 nanometers; extreme UV radiation is going to be like 100, 80 nanometers. Something much, much shorter. And to accomplish that is very difficult, especially if you want it to be really usable light. We would like to understand how solid-state high harmonic generation works, and then we want to be able to basically control it and use it. With solid-state high harmonic generation, you can get an attosecond pulse train. This is extraordinarily fast. We are limited by our current lasers, which are femtoseconds. What's the difference between femto and atto? It's incredibly difficult to fathom, but the classical analogy I've heard is this: essentially, the attosecond timescale is comparable to the timescale of one second compared to the duration of the existence of the known universe. So that’s the goal: getting on the attosecond timescale. And yes, I like it a lot. It’s really fun.

THAT'S A UNIQUE DEFINITION OF FUN ….

I try to have fun in everything I do, and grad school is certainly enjoyable to me. This field is new, and it’s so mysterious. Solid-state high harmonic generation was discovered as a possibility in 2010 or 2011 – basically a decade ago. People were like, wow, that’s really interesting. How on earth does it work and how can we control it? And 10 years later we’re still asking those questions. It’s new. It’s cutting-edge. And we can work with people across other departments, which is just a joy. I like working with interesting people. So this is my version of fun. 

ANY ADVICE FOR PROSPECTIVE GRAD STUDENTS?

I would say, first go on a visit. Give the place a try. When I did this, I tried to read a couple of papers from every professor whose group I was interested in. I didn’t have to understand everything from that paper, but I’d write down my questions and I’d go in with a very open mind to talk with the professor. You should feel like this is the style or the group for you, because it’s kind of a long-term partnership. Then, you should meet with the graduate students. How are they doing? What do they like about the program? Talk with people in various years. And then in the evening, after the visits, I would write down my reflections from the day. Type it up. Write it down. Have it in a book. Anything that can help you remember back as you make your decision. 

WHAT OTHER PROGRAMS DO YOU ENJOY ON CAMPUS?

I’m the treasurer of Princeton Women in Chemistry. It’s a fantastic network of students, postdoctoral fellows, faculty, and staff dedicated to supporting and promoting women in chemistry. We recently started a mentoring program for undergrads, grad students, and postdoctoral fellows. Also, I really love the GradFUTURES Mentor Collective. I did not know about this program until I thoroughly read through the emails I got from them. They partner you with a Princeton alum who finished their Ph.D. in a field relevant to you. So I filled that out and now I have a mentor. I matched with someone who graduated with a degree in MAE and I talk with them from time-to-time when I have questions. It’s so valuable. It’s nice to have someone to turn to for advice on things that you’re encountering in graduate school from someone who has that experience, but who can approach the questions from an outside perspective. I’ve learned some new tricks from my mentor regarding how to maximize making progress on a monthly and weekly basis. It is quite fantastic!