Researcher of the Month
November 2010
Gaku Nagashima
Physics Major, Class of 2011
URECA Summer 2010
Mentor:Dr. Dominik Schneble, Physics & Astronomy
At SB's LASERFEST on Nov. 9th, you can learn how lasers work, meet Spectra, view laser light shows—
& even attend a poster session featuring laser projects! Take some time to talk with
URECA's Researcher of the Month, Gaku Nagashima, who will be among the poster presenters
engaged in telling how he uses lasers!
For the last year, Gaku has been hard at work on high-precision laser spectroscopy
and frequency stabilization of a laser system working under the mentorship of Prof. Dominik Schneble. A resident of Shimane, Japan, Gaku received his high school diploma in mechanical
engineering from the Matsue College of Technology, Shimane, Japan; and then completed
a year of coursework in Diablo Valley College, Pleasant Hill, CA prior to transferring
to SB in 2008. Now happily settled in at SB as a physics major, Gaku has taken the initiative to get involved in hands-on research and learn
as much 
physics as he can, regularly attending departmental colloquia, and enjoying his interactions
with the physics community here. In his first semester at SB, Gaku began working with
Prof. Clark McGrew on an international collaborative particle physics project, and was involved in analyzing
and characterizing MPPC (multi-pixel photon counter) noise in the Pi Zero Detector
for the T2K experiment in Japan (Nov.2008-Dec.2009). A growing interest in lasers sparked a conversation
with Prof. Dominik Schneble, who offered Gaku a position in his Ultracold Atomic Physics research group starting
in 2010—coincidentally, the year celebrating the 50th anniversary of the Laser! And here in the Schneble laboratory, Gaku has thrived— in particular, learning by
doing!
Gaku developed and built a sophisticated electronic locking box for stabilizing the
frequency of a high-power diode laser: he was able to demonstrate a linewith of 1
MHz, which is a factor of ten better than what the commercial system had been capable
of! Supported in summer 2010 with a grant from URECA, Gaku currently works on a precise
spectroscopic determination of rubidium background vapor pressure in an ultrahigh-vacuum
chamber, and will be presenting at LASERFEST on Nov. 9th, and at the URECA Celebration, the campus-wide research symposium, next April.
Gaku was inducted into Sigma Pi Sigma, the physics honors society, in April 2010; and plans to pursue a Ph.D. in applied
physics, following graduation in May 2011. Gaku's hobbies include playing guitar (his
band performed last April at Japan Night) and he enjoys performing Aerosmith, Mr. Big, and Deep Purple! Below are excerpts
of Gaku's interview with URECA Director, Karen Kernan. 
LASERFEST www.laserfest.org
Check your optical clocks!
It's time to celebrate
the 50th anniversary
of the LASER!
Karen: What was your project about?
Gaku: I’ve worked in Prof. Schneble’s research group since January. Our goal was to stabilize
a laser in order to conduct some experiments such as absorption imaging, or laser
cooling. The project involves setting up Doppler-free spectroscopy; using it to characterize
the frequency stability of the laser; designing and constructing feedback control
loops...This summer, I worked on developing electronics, building circuits. Before
this summer, I didn’t even have that much experience with circuits. I didn’t imagine
I could build an actual locking box to stabilize the laser. I didn’t expect that much.
It turned out to be really successful.
How do you know when the laser is stabilized?
We set up spectroscopy. The spectroscopy cell has rubidium atoms, and the rubidium
atoms get excited at a certain frequency… by looking at the response of the atoms,
we can precisely know the frequency of the laser.
How did you first get involved with Prof. Schneble’s research group?
I took Prof. Schneble’s class in my third semester here. I thought he was a really
good lecturer—really spirited and humorous. And I wanted to work on a real practical
physics project. Lasers are used in medical, industry, everywhere …so I thought it
would be very interesting to work on lasers, to try to understand the basic concept
of the laser.
A great year to get involved - the 50th anniversary! What are your plans now? Are
you thinking about going to graduate school?
Yes – in applied physics. My primary interest now is lasers, and optics applications.
How has being involved in research prepared you for future graduate studies?
I think one reason I wanted to be involved in research early on was to be able to
communicate with professors and with people – I thought it would be great to have
the opportunity to talk with people about physics and academics …. Most importantly,
I wanted to find out what I like specifically. Sometimes it is very difficult to know
what’s most interesting in your field until you’re actually doing the work. You can
have some idea of what seems interesting to you, or what’s important, but acquiring
knowledge of how physics actually works through experience in the laboratory is the
best way to find out what you like doing.
What do you like about working with lasers?
With this particular work, developing the lock box, I can see consequences very easily.
If you think and do all your work at a desk, it could be difficult to know what the
consequence of your work is –but with this project, I was able to work on the laser
closely. I was able to build an improved product to stabilize the laser. Because I
have my own project with Prof. Schneble’s group, and am doing most or all of the work
myself, it’s really easy to see the result, to see the product getting completed.
You mean, because you get constant feedback, you can see how you’re progressing?
Yes, exactly. If I work at it, I can get results, consequences. And when it works,
it’s a great pleasure to see that it’s working….
How would you describe your research group/environment?
It’s very good environment to work in…and I learn a lot of things from the others.
There are 3 PhD students, and one master’s degree student from Germany. We are all
doing separate projects but the others are always real eager to help me. One grad
student taught me about electronic circuits, how to solder circuits.
Have you always been interested in physics or engineering?
I was interested in physics back when I was in 9th grade, at the beginning of high
school. Physics is a very fundamental subject, a powerful thing to study. . . I was
always so impressed by learning about the work of Einstein and Newton, those great
scientists.
What made you decide to come to Stony Brook?
I decided to come to the US around 11th grade summer. My English was not good enough
to get into university then. So I decided to go to community college at first, and
chose a school in California. Later on, a friend told me that there is a very good
state university in NY. I asked my physics professor about it. He told me Stony Brook
is well known for physics. When I looked it up, I could see that SB was quite reasonable;
and really good for physics!
And you became involved in research that very first semester you came to SB?
Yes, in 2008. I was really lucky to get involved in that high energy physics project
– to work with Prof. McGrew. It was a big project, a huge collaboration where each
group of universities builds their own detector and brings it to Japan. Eventually
our group went to Japan to install the detector, and I worked to analyze noise characteristics
of MPPC (Multi pixel Photon counter) for the detector calibration…it was a great experience.
What was the most challenging thing about the work you did this past summer?
When I build electronics, if even one thing goes wrong, everything doesn’t work. So
I had to look it over one by one, all the components. Sometimes a capacitor is broken
and you cannot see it from the outside. I have to check them one by one, and it takes
time.
That must require patience!
Yes! I had to stay late when I was putting things together.
And what was the best day with your research?
When I locked the laser, and the laser frequency got stable…that moment was really…"WOW”! That was great! Even the professor told me he didn’t expect this much quality. I
was so glad that I could achieve that. . . I really appreciate that Prof. Schneble gave me this project. You know, there’s always a certain risk that you could break
the laser when you try hard to improve its performance. So I really appreciated that
he gave me this project, that responsibility, regardless of that risk. I felt very
lucky to work on this.
How does your mentor help you on the project?
He’s really good at conveying the essence of the problem so that I can understand
that point and learn— and then go work myself. If I have some more questions or problems,
I just ask him.
Do you think you’ve gained a lot of knowledge by doing research?
Yes. A lot! I learned about circuits, about spectroscopy. . . basic, really important
techniques. It was relatively independent, the work I did on building circuits …I
learned a lot.
Are you excited to be part of LaserFest?
Yes. I’m preparing my poster now. This is the first time I am making a poster presentation. It takes time....
What advice would you give to other students?
I think some students are afraid of talking to professors. But professors are really
accepting. They are really kind. I’m cannot speak about other departments. But at
least in physics, I have found that they are really helpful, and welcome undergrad
students to work on projects. So my advice is just to talk to your teachers … if something
sounds interesting from class, or if you have any chance, it’s always good to talk
to your professors. I also go to the colloquium that the department has every week.
I try to go there every week. It’s difficult to fully understand the talks, but still
good to learn about new fields.
Physics is a great department!
Yes, I like the department very much. I think the courses here for physics are really good. Professors are really prepared
and organized, they are really eager to help students. Especially as you go to advanced
classes, the class size gets smaller, and it’s easier to talk, and to discuss things.
I’m taking a laser class right now with Prof. Tom Weinacht that is very interactive,
very interesting.
All in all, then, you’ve had a positive experience at SB?
I’m so lucky. I think coming here was a really good choice for me….I appreciate the
friend who first told me about the university!