Weekly Progress
Week 1
This week I met my advisor and the
other REU students, and I got an introduction into my project. It is our
group’s beam time, so I mainly learned about what we do in lab and did a lot of
reading. We have lectures from Dr. Weaver that can get quite interesting.
Ryan’s design for
our t-shirt
Week 2
This week I worked with one of my grad
students to set up a saturated absorption arrangement. We need these to lock
our lasers to certain frequencies. I also started working on a shutter device
that I will use to switch my laser on and off. We started an electronics class
this week, covering just some basic stuff that we should know in the lab. We
also had a shop class to become familiar with the shop tools.
Week 3
I continued work on my shutter, and so
far things are going pretty well. The circuit that I am building has a couple
of components that we are having some trouble finding. The shutter design and
circuit was adapted from Robert Scholten’s design, which can be found here.
My shutter
circuit, mounted in the box
Week 4
This week I completed my shutter, now
I just want to check how fast it is. I also started looking into how I am going
to do the optical set-up for my experiment. It will involve using an
acousto-optical modulator (AOM), so I have to learn more about what that is and
how to use it.
My completed
shutter
Week 5
I continued working with my set-up
this week, but our group has beam time again so I can’t block my laser beam.
Instead, I am working on the connections for my AOM and adjusting the power
into the AOM. The voltage controlled oscillator (VCO) that I was planning to
use to control the AOM doesn’t appear to be working properly. I’ve also had to
have cable made for my connections, because we do not have a lot of SMA to BNC
cables around. Instead of the VCO, we substituted an oscillator generator and
used that to try to line up my AOM.
This is a mot. It
is the brightest speck in the middle, and is bright due to fluorescence.
Week 6
I encountered many problems with my
AOM again this week. I went back and looked at the VCO that wasn’t working
properly and found another VCO in the lab. I compared how these two were
working, and it appears that the first VCO is dysfunctional. Now I am working
to use the second VCO. I also received an email from Dr. DePaola that mentioned
a mixer as part of the VCO connections, and I was unaware that I needed one. It
turns out that it is very helpful.
Week 7
Once I had all of the equipment
necessary to get the AOM working, I finally got it lined up and looking good.
There were several problems with space on the table for alignment of my lenses,
but I managed to re-work the set-up to make it fit. Now I am starting to set up
the fiber optic cable that I need to transfer my beam to the MOT, but once
again it is beamtime.
This is the mess
that has my electronics for the AOM…
Week 8
Beam time ended on Monday, but we were
able to keep the beam until Tuesday morning. Then I began work on lining up my
fiber. This turned out to be harder than we expected. I had to redo my set-up
again to make sure everything would fit nicely. The fiber launcher that I am
using is a bit tricky to line up, so I learned how it is adjusted as I went.
But I did eventually get it. I also started to line up my beam through the MOT.
Right now the camera that I am going to use for imaging is still being worked
on for timing and other technical things. So I am using a different camera to
check my alignment.
Week 9
This week I rearranged my set-up to
make it more accessible. I also was able to get a decent image of the beam
through the trap, but not able to image the mot. The beam out of my fiber is
spatially ugly, which is not what we expected. We think that the fiber may be
dirty or damaged, but will fix this in the future. We have also discussed a
couple of different timing mechanisms for imaging. I’ve also done work with my
final report, since we are giving those early next week.
This is a picture
of my probe beam that goes through the mot. It is a little difficult to see,
but is the somewhat bright circle.