21 June 2006
Mike, Stephanie and I have been at Stony Brook for about a week now so I guess its time to start our journals. So far we don't have any individual projects to work on. We have spent much of our time reveiwing optics and Dr. Noe has also given us many demonstrations with lenses, lasers and various optical toys. Dr. Metcalf has also given a few lectures on laser cooling which we and a few soon to be graduate students attended. I suppose the most basic, important idea is that atoms will absorb light of a correct frequancy, and this light will transfer momentum along with energy. The linear momentum will then slow the atom down, thereby cooling it. I think one of the most interesting aspects is that the atoms have to be cooled down to about 30 mili Kelvins before you can use the laser system to cool them down to micro Kelvins. Dr. Metcalf also told us that an important application of laser cooling is for atomic clocks.
Yesterday the REU program arranged a luncheon during which many heads of departments talked to us about grad school. They discussed the application process, GREs and what people look for in a grad student. It was a very informative meeting and everone picked up nice booklets on the various grad programs. I picked up physics, engineering, and biophysics, since I still don't know what exactly I am interested in. Later that day Reinhold Blumel from Weslyan University visited and gave us a short talk on his interests and experiments in physics. He reveiwed the Schrodinger equation for a partical in an infinite square well, and the wave nature of matter. He then explained that he was trying to link together classical and quantum mechanics using density of states.
Oh, and earlier that day Maaneli took us to where the phsyics
department has liquid nitrogen on tap, and we played with that for a
29 June 2006
I am finally done with my presentation!! The highschool students
started this week (victor, matt, hamsa and scott) and we undergrads had to
give them presentations, hopefully catching them up in their knowledge of
optics. Stephanie did a power point on complex numbers, i did mine on
Fermat's principle and ray optics, and Mike is presenting today on
interference and diffraction. We also went to David Cardoza's PhD defense
yesterday, which was very interesting. He works with short pulse lasers,
studying the controlled breaking of bonds in molecules (in extremely
simple terms). Sooooo now i have to get back to thinking up a project.
Also, Happy Birthday Anna :-) .
7 July 2006
This week was a short one due to the 4th of July holiday. Over the holiday weekend I went to Rumney, NH to go rock climbing with some friends from Uconn. There is pretty much no climbing on long island, so I am very out of shape. I will have to frequent the gym to maintain my upper arm and shoulder muscles, and run on the treadmill to get endurance for the hikes to the climbs. One of the approaches to the climbing area was ridiculous; very steep and hard to do carrying gear etc. I'm just very out of hiking shape.
During the three days of work this week I've been looking on line,
hoping to find something interesting to base a project off of. I'm very
interested in materials, but it would be a good idea for me to do
something related to microscopy since that's what Dr. Gibson is working on
(what I'll be doing for my senior honors thesis). I'm probably changing
my major to Materials Engineering Physics, so maybe next year I'll do an
REU in the material science field :-) .
10 July 2006
Lately I've been reading about various types of microscopy on line trying to think of a project idea. Marty Cohen had suggested doing something with confocal microscopy, at least maybe setting up a one of the microscopes objectives we have to simulate it. Usually flourescence is used where a focused point of light is scanned across a specimen and the flourescence is detected by a photomultiplier which creates the image on a computer. The flourescent light is sent through a pinhole before going to the photomultiplier, to clean it of secondary flourescence, creating a much clearer image. I also read about phase contrast and differential interference contrast microscopy which use the different indeces of refraction of the specimen to create an image. Total internal Reflection microscopy creates an area of total internal reflection in the microscope slide, so that only the evanescent waves cause the specimen to flouresce. Since the evanescent wave field is only about 100 nm "thick" compared to the 1000 nm that confocal microscopes usually penetrate into the specimen, there is less secondary flourescence, giving a better signal to noise ratio and a clearer image. However, I'm not sure if anyone has made a TIRM yet, the website I was at only gave the theory, and didn't mention any working microscopes or current research using one. I'll probably look into that tomorrow.
Dr. Noe juat mentioned the interesting topic of Moire magnification,
so I'll probably also research that tomorrow. Stay tuned for that journal
entry. Now I'm off to dinner.
So I looked into Moire magnification but couldnt find much explaning
the actual concepts. There were a couple articles about using the
technique to look at errupting molars, but nothing i could use for a
project yet. I did come acroos a few nice sites that have fun applets
about the Moire
phenomenon (see link). Then Dr. Noe and I played with an optical fiber
for a while. He notices that when you hold an optical fiber right up to a
two dimensional diffraction grating like the 3-D glasses an interesting
checkerboard pattern appears. He is not sure why this
happens: Dr. Metcalf suggested reflections off the grating, so i that is
an idea for a project or mini project for people if more information can
be found. Dr. Noe later told me to look into phase contrast microscopy
becaue he found a paper that might give an easy experimental setup. He
also told me to lok into the Abbe theory of diffraction in a microscope
and inverted optical tweezers, since they have previously worked on a
normal optical twezers set up.
July 14 2006
Well i don't quite have a project yet, but i'm hoping I can find a way to make a phase contrast microscope. The Strong book on optics said they made a phase plate by scoring a normal plate of glass with some HF, so maybe I can look online and find more simple ways to make a phase plate. Dr. Cohen suggested that I could probably also find a coated peice of glass and remove the coating from the middle. I didn't get to look into simple phase plates today, so i'll probably do that monday or over the weekend if I get a chance.
I've also been reading about Abbe's theory and his resolution limit equations. Yesterday I found a very good pdf file about his theory and what is sometimes missing from college optics textbooks, so once I have that all read and understood I'll put a link to it on my links page. I also spent a while yesterday and a little today revising my links page. I have a template from Lidya's website, and I still have to get rid of her Talbot links and add a few more of the sites that I've found. From working on the page, however, and writing in this journal, I'm quickly getting the hang of using linux and html format. OH, and I read about numerical aperture, which is related to the size of the finest detail that a lens can resolve, and F number (focal length over diameter of the lens), which is used in photography a lot. The numerical aperature is related to the F number by the expression N.A = n/2F. So a large F number means a smaller numerical aperture (in photography you can take n as 1, since the light is just traveling through air into the lens.) Mike brought in his juggling balls for a little while one day, so I also learned how to juggle; that was fun.