Carrier-Envelope
Phase
by Brett Chrisler
Advisor: Vinod Kumarappan, Associate Professor
of Physics
Kansas State University Physics Department REU Program
Project Overview Research Description and Progress Final Presentation Lectures Ethics class About Me
Project Overview:
Mode-locked femtosecond lasers create a
sequence of pulses. With a moving pulse, the carrier-wave and the envelope
travel at different velocities, the first with the phase velocity and the later
with the group velocity. The difference between these two results in the
carrier-envelope phase shift and the offset frequency between them needs to be
obtained and stabilized. In this experiment, we used a self-referencing f-to-2f
interferometer to obtain this offset frequency.
Additionally, I assisted on a pump-probe
laser experiment to research electron diffraction of aligned molecules. This
setup required a laser beam to be separated into two paths, one of which is
called the pump and the other probe. The two beams later overlapped and crossed
with a gas jet inside a vacuum chamber. The delay between the pump and the
probe can be changed after the spatial and temporal overlaps are discovered.
The pump vibrates the molecules in the gas, and then the probe ionizes these
molecules. The electrons that are stripped are sent through a microchannel
plate onto a velocity map imaging system and recorded by a camera.
Research
Description and
Progress:
For
a full description and progress view my final presentation and Eric Wayne
Moon’s abstract of a dissertation “Carrier-Envelope
Phase Stabilization of Grating-Based Chirped-Pulse Amplifiers.”
Click here to download my
presentation in PowerPoint and pdf formats.
Since
there were a variety of topics covered during lectures, I gained knowledge in
all fields of physics. Every presentation contained exciting material that kept
me engaged. All the instructors that presented were extremely informative on
their topics. I struggled to understand some of the topics in the quantum
mechanics area, but I know learning some knowledge about these topics will only
assist me in my future courses.
Ethics class was run by Professors
Bruce Glymour and Amelica Hicks. I gained knowledge in many areas in ethics:
guidlines, diversity, plagiarism, fraud, co-authorship, framing, advocacy, and
mentoring. Every class was open for discussion to gain different viewpoints,
which allowed everyone in the program to have input on the topics presented.
About Me:
I
attend Fort Hays State University and I am an
undergraduate pursuing my B.S. in physics. Furthermore, I am a tutor for the
department and Secretary of the Physics Club. I first became interested in
physics when I wanted to obtain a degree in meteorology and atmoshperic
science. Now, I hope to pursue a career in medical physics or radiation
oncology. In my free time, I love to run, sing, and socialize with friends and
new people.
Future REU Students:
I would highly recommend the REU
program to any undergraduate student that wants to experience research. The
K-State REU program gave me insight on what happens on a graduate school level
in the laboratory and also allowed me to gain knowledge in many areas of
physics. Furthermore, the other students I met on this summer program I gained
amazing friendships with that allowed for personal, academic, and professional
growth. There has not been a better opportunity than this undergraduate program
so far in my college career, and I would definitely want to have this
experience again if given the chance.
This program is funded by the National
Science Foundation through grant number PHYS-1461251.
Any opinions, findings, and conclusions or recommendations expressed in this
material are those of the author(s) and do not necessarily reflect the views of
the National Science Foundation.
Useful
Links:
I
have found the following links particularly informative or useful: