Mohammed Hassan has been preoccupied with one question since his student days: How do electrons move in atoms? Now, as Professor of Physics and Optical Sciences at the University of Arizona, he is investigating this question. He runs the Attomicroscopy Lab there. Between 2009 and 2013, he was a PhD student in the attoworld-group and a student of the IMPRS-APS. Following his postdoctoral research with Nobel Laureate Prof. Ahmed Zewail at Caltech, he joined the University of Arizona. In this interview, Mohammed talks about his current research, his advice for young scientists and the philosophy within his group.
Can you tell me about your research?
I try to blend the attosecond expertise I have learned at the MPQ under Ferenc Krausz’ supervision with what I have learned at Caltech from working with ultrafast electron microscopes to come up with a new direction of research: Attosecond electron microscopy, or what we call in our group “attomicroscopy”. We use this new tool to image the electron motion in real time and space. And the nice thing about it is: It’s not just a tool for physics, but can extend to different areas of science. It can have an application in chemistry, in material sciences, in biology. For example, I think if we’re able to image the electron motion in molecules, in proteins, this is could open the door for discovering new drugs or discovering the core problem of some diseases.
Another thing which we are doing here in my group, based also on controlling the electron motion inside the material, we’re able to demonstrate the capability for controlling the properties of matter to establish what we called, ultrafast optoelectronics – very, very fast electronics. And this is the applied physics part in my research. The big dream is to have an ultrafast transistor which means all the electronics we are using today, smartphones, computers, etc. should be like 1 million times faster. You can think about the implication of that in the stock market. When microseconds make a huge difference in taking a decision of selling or buying some stocks.
Also, recently, we have extended our interest to convert classical laser light to quantum laser light, which allows us to open a window to the quantum world. And we’re able to measure for the first time as the ultrafast dynamics of uncertainty, which is completely new.
How did you get interested in attosecond physics?
Since I was in high school, I was fascinated with mathematics and the general physics problems which we studied in high school. But when I started to study physics and chemistry in my undergrad, I was always asking myself how the electrons move inside the atom. We learn how to fill the electrons in energy states. And I was thinking: Is the electron just moving from an energy state to another energy state when it’s excited? And this popped up many questions in my mind, which I didn’t have an answer to. So, I started to search for a place with a new tool to see and control the electrons. And this is how I found the Max Planck Institute of Quantum Optics …
What is are challenges young scientists currently face and which advice would you give to them?
For young scientists, I think the big challenge is that the picture is not clear in their mind what exactly they would like to do. And this is a big, important question. Because based on answering this question, you can identify which route you would like to go. So, it’s important to have a clear thinking, to have a clear plan and to be flexible in your plan, because sometimes it’s not going to work. And this will help you to build a strong portfolio and a strong career.
Basically, be coherent like a laser in building your career to reach your goal. This is the difference between the incoherent light. It goes everywhere. And there’s a coherent laser which is pointed directly to the goal. So, try to be a laser. This is my advice.
Do you currently have any collaborations with attoworld?
I may not have a direct, scientific collaboration, but usually when I need an advice, I communicate with my supervisor, with Ferenc, and my colleagues there – they are doing fantastic science! Sometimes you feel like “I would benefit from their opinion”, right? Sometimes you are doing an experiment or you would like to do a certain experiment you are not sure about and you want another trusted mind to think with you. This type of indirect collaboration discussing science is very beneficial for both of us, I think.
Do you currently have any open positions?
Absolutely. We have a Postdoc opening and I would be more than happy having a talented scientist!
What is your team like?
I try to keep my team small. I have tried to keep the ratio between PhD students and Postdocs one to one, and the goal is to have three PhD students and three Postdocs. And they are coming from different cultures and places, which is something I learned from IMPRS-APS can be beneficial.
Also, I’m doing something which is a little bit strange … but I keep going to the lab and doing the experiments with them. I would go to the lab and discuss with them, not just small meetings every week. My goal is not to force them to do something, but rather not to make them reinvent the wheel. Sometimes I feel like they need to – even if I know the answer – try something to see if it works or not, because they learn in this way. But sometimes they don’t have to spend all the time and the effort in repeating something which we know already the answer for. I can tell them what I have learned and they can build on that knowledge.
What is it like living in Tucson, Arizona?
Living in Arizona is very nice. It gets hot into the summer, but I am used to it. I have been here for seven years and a half now. Generally speaking, I love the places which support me to do the science I want. And this is the first criterium for me, for choosing the best place for me. Since this was the case for Arizona, I love it. It’s a small city also. And it’s family friendly. You don’t have to drive too much. It has a lot of nature views and canyons and mountains. So, it’s good sometimes also to relieve the stress of science by going to these places and even do some outdoor activities. And, we have Mount Lemmon. In the winter you have snow and ski activities there, which is also nice.
You can watch a longer version of this interview with a focus on Mohammed Hassan’s time at the IMPRS-APS here.
Interview: Nina Beier
