## Research Journal## August 12,2014The award/closing ceremony for the Simons program was today. It started with poster presentations and then ended with awards being given out to all the students. It was nice seeing the completed LTC posters and it was interesting seeing what everyone else did during the summer. There was a big range of posters, in content and in presentation. There were posters on which is the best sport for kids to listening to the frequencies stars produce. Some posters where easier to read and had nice diagrams while others were packed with information. After the closing ceremony, the lab and some of the kids parents went out to eat at the Simons cafe. It was a nice goodbye lunch and I realize how strange its going to be not seeing everyone everyday. This summer has been a great experience and I really appreciatie everything the LTC, Dr. Noe, and Melia have done for me and for the program. ## August 11,2014Today was the group's last day in lab, which is kind of bittersweet. It has been wonderful working with everyone and watching the high school students grow has made this experience even better. In the morning we cleaned the lab up, I didn't realize how messy it had become until we started vacuuming! Then in the afternoon we gave a tour of our lab for the other Simons Fellows. I ran the laser light show where we used three different colored lasers to great complex patterns on the ceiling. For an even cooler effect we gave everyone diffraction glasses so that you would see more patterns. ## August 8,2014Today is our last Friday in the lab, its hard to imagine that this summer has gone by so fast. With the end of the Simons program on Tuesday and a lab tour on Monday, the day has been spent cleaning and finishing up posters. I've mainly been doing computer work lately like working on a report page for my white light interferometer and compressing photos. ## August 7,2014This morning Rachel gave us an overview about the properties and applications of SLMs. I honestly didn't know a lot about them, besides the fact that Rachel had done a project with one and had used SLMs over the summer, so overall her presentation was very useful to me. While looking up some topics I stumbled upon a riddle called Einstein's puzzle. Einstein's puzzle is basically a very long logic puzzle to try and figure out who owns a pet fish and I personally think it was pretty fun to solve. Here's the link to a webpage that describes the problem, just don't scroll down too far or else you'll see the answer! ## August 6,2014This morning I downloaded OpenFringe in hopes that I could analyze interferograms with. It seems to be specifically designed to measure the surfaces of mirrors but hopefully I can apply it to what I need to do. I ran a few interference patterns through it and got interesting results though I'm not sure if the program is accurately showing what is going on.
At our pizza lunch we had Rachel give a talk about her REU experience at University of Rochester. It was cool to see what she has been up to and I hadn't realized that her work there was sort of related to quantum cryptology. I had read about quantum cryptology the other day and had found it very interesting. Another option I have with my interferometer is to change it into a Twyman-Green setup and image the surfaces of mirrors, lens, and microscope objectives. This might be a more feasible option since I'm not sure if getting a new translation stage is going to practical in the time that I have.
## August 5,2014Today I played with the new CMOS camera we got. I captured the interference patterns created using a white light source and the red jumbo LED using various lens.
It appears that maybe the casing on the LED caused some aberration towards the left because the image appears brighter there. I also looked into different interferogram analysis programs and narrowed it down to two programs: IntelliWave and ATMOSFRINGE. Even if I might not be able to get to the imaging step, its good to know whats out there for future reference and future students. ## August 4,2014This morning Ikaasa showed us the derivation of the Law of Malus from Jones calculus. The Law of Malus
where I=intensity, I In the afternoon I puzzled more over how to move the translation stage without having to exchange it for one with a differential drive. I don't really have any great ideas. If all I needed to do was to move the mirror without knowing its exact position then I could just use a rubberband. If this doesn't work, I could also do something else with the white light interferometer for Fourier Spectroscopy. Jon Wu did this a few years ago but maybe I could do a variation on it? ## August 1,2014This summer has really flown by, I can't believe that it's already August! Today I worked on settig up the sodium lamp and producing its fringes. This required me to steal various parts from the other sodium lamp we have but I eventually got it up and running and mounted. The bulb at the moment has some difficulty triggering on but I have solved that by hitting the bulb repeatedly. I can see the fringes which is spectacular! The bad news is that I can see them through the interferometer but have so far been unable to project them onto the screen due to the light source being extended. After aligning with the sodium lamp, I switched to a white light source. I could automaically see faint white light fringes!! That means the paths of the arms are within one micron of each other. Dr. Noe suggests I buy a lottery ticket. ## July 31,2014
This morning while the Simon's kids worked on their abstracts, I figured out a problem Andrea was having with her webpage
and server. It turned out she had multiple files of her journal with several different names, so she was saving her edits
to one of the non-published pages instead of the regular journal.html file. I'm not really sure how she got so many files
but I went through their content and slowly deleted them. What was strange was that some of the files were connected, as
in if I opened one it would redirect me to another. Luckily it is all
fixed now and hopefully this won't happen again! For future reference to
delete a file using the command I also found a lab experiment done in a physics lab at University of Washington that describes a gradual way of finding white light fringes by going from laser light to a sodium lamp, white light with a green filter, and finally to just white light. ## July 30, 2014Today we gave research updates at lunch. It was nice seeing where everyone is at with their projects. I spent the rest of the day helping out around the lab and thinking of a way to effectively control my translation stage. At the pizza lunch, Hal suggested using a differential screw which I think would be pretty effective. I've been looking through the ThorLabs catalog for a differential drive or a translation stage that comes with a differential drive. I've narrowed it down to two things a translation stage(PTIA) and a drive(DRV304). It has been kind of hard trying to choose between the two because they both have their pro's and con's. For one, the translation stage comes already fitted with a differential drive and is overall cheaper but the stage drive is also not as percise as the DRV304. The DRV304 is very percise but it also costs about the same as the translation stage and may not be compatible with most of our current translation stages. I've made an excel sheet comparing the two so hopefully that'll help me decide which would be the better fit for the lab in general. ## July 29, 2014Today Andrea showed us calculations she has been doing for her sonoluminescence experiment and the basic derivation of how 1 decibel is related to the logarithmic ratio between two pressures. After that the rest of the group went to the conference room to discuss abstracts while I stayed behind to finish toying with my interferometer. I decided to check its alignment using the HeNe laser, and found that I could create the circular airy pattern but it was quite faint in comparison to the central bright spot. Maybe the intensity of the laser beam is too great? In the afternoon, I played with the red LED light source along with the motor Kathy used for her project. It would be possible to use the motor to slowly move the translation stage so has to move the fringe pattern. The passing fringes can then be counted by eye or by the use of a photodetector. It would be easy to see the passing fringes using laser light but by using white light the fringes would pass more quickly and it will be difficult to count without aid. I then spent a bit of time talking to Andrea about her project and some of the math behind it and suggested that it would be good to get a basic understanding of calculus before proceeding. This resulted in her and I going over some of the simpler ideas of calculus and some of the multivariable work that she'll need. It was nice helping her out and time really flew by, before we knew it it was alost 6. ## July 24, 2014I've spent today trying to switch my light source in my interferometer to a red LED. I've so far mounted the LED onto cardboard, mounted the cardboard onto a post, and have attached it to a controlled voltage source which allows me to use the LED without a resistor as long as I'm careful not to overload it. Finding a suitable lens to collimate/focus the beam has been annoying. I have so far tried a 10x objective lens from a microscope and a lens with a focal point of 25.4mm or 1 inch. It's been frustrating because neither focus the LED light perfectly, meaning a large part of the beam is diffuse, and there is a lot of light that escapes along with aberations. I think I might try first to find the right distance between the lens and the LED, couple them together, and then try and find the right position from the beam splitter. ## July 23Today Ikaasa gave a board discussion about Jones Calculus, which is a way of characterizing polarized light mathematically. I've been able to make the beams collinear but what has been difficult is to keeping them collinear and adjusting the path lengths. Somehow my equipment keeps getting bumped so everything gets unaligned which requires me to have to spend a bit of time just realigning everything. I think I need to just permanently screw everything onto the table before I go any further so as to try and prevent that from reoccurring. Eden's group gave a presentation at the pizza lunch about what they do in his lab with quantum information. It was all pretty interesting, and it was nice seeing other undergrads/grad students' work! I actually later ran into Eden at Starbucks and had a nice chat with him. ## July 22, 2014Today I derived how to get the interference equation for a single slit which I learned last semester in my freshman physics class. Overall it isn't too hard to understand, there is just a lot of steps in the derivation. After that I helped Ikaasa gather lights to test with the new spectometer we just got. It is actually pretty accurate but does have a lot of feedback, we actually got the exact wavelength of one of the HeNe lasers we have. I read a paper on frequency-domain analysis of white-light interferomtry and made a page compiling some of the papers I've read, which can be found here. I'll eventually post progress pictures and more specific updates of the work I'm doing. I also spent a lot of time just playing with my interferometer, adjusting the mirrors and watching the interference patterns. The mirrors got aligned in such a way that the entire bright spot would practically disappear. The occurs of maxium interference can be shown through the equation: where m=an integer, λ=wavelength, and 2d=path length difference of the two arms of the interferometer. So from my understanding, we will have destructive interference when the path lengths are the same(d=0), and when the wavelength is a half integer multiple of the wavelength.
## July 21, 2014This morning Melia talked to us about where the equation,, originates from. First we have to look at the intensity of an airy disk which is demonstrated by the function:
To find the dark rings of the airy pattern we need to find the zeros of the intensity equation
which happen when the bessel function of the first kind (J
I took apart my orginal interferometer set up, rearranged all the mirrors and found a laser and a objective lens from a microscope thanks to Marty. After a while of adjusting the mirrors I was able to create fringes! ## July 18,2014In the morning, I finished mounting the mirrors and the beam splitter for a basic Michelson interferometer now I just have to align everything. We also had a morning discussion about integrals. Dr. Noe also talked to us about diffraction through a double slit and the difference in amplitude. This reminded me of a physics problem I had last semester where we used Fourier transforms to derive interference equations. The math itself isn't difficult after you understand it but the derivation looks very intimidating. We also got to take a break and see the ending ceremony/presentation of an engineering camp on campus. They showed off various robots/gadgets they made such as a microphone and a robot that follows a dark tape. It looked like they had a lot of fun and makes me wish I did something like that in high school! ## July 17, 2014Today we got to experiment with the lasers in the lab. We set them up to shine through different diffraction plates (circular, square, and triangular) and then oberved their diffraction patterns. Melia then asked us to try and figure out the wavelength of the laser we were using by utilizing the equation:
where D=diameter of apperture, θ=angle of resolution, λ=wavelength of light. Initially we got a value that wasn't too far off from the true value of the laser but as we kept taking measurements it got less and less accurate. The main reason I think this happened is that we were taking measurements at farther and farther distances thus introducing more error. In the afternoon Melia, Dr. Noe, and I went to a grad studentin the BEC lab's oral examination. Surprisingly I knew some of the general things he talked about from the pizza lunch meetings such as supercooling and the BEC. Even though I didn't understand most of it, it was interesting to watch and to know if I decide to get my PhD that I would have to complete that to proceed with my thesis. After we returned from the examination, Dr. Noe cleared off an area so that I can build my interferometer. I'm using materials used in the past to build a Michelson interferometer. I think I'll initally build a Michelson interferometer for practice and then modify it to make it a white light interferometer. ## July 16, 2014Today we presented topic proposals before our weekly lunch meeting. . I have decided to build the common path interferometer described in paper 262 written by B. Wiesner, O. Hybl, G. Hausler in 2012. We haven't quite decided yet what we'll do with the interferometer, whether we use the 4 LED light source from the paper or study something completley different, but the process of building it will be a project in itself. Marty told us a real life application of the device, opthalmologist actually use white-light interferometers to image your retina. At the pizza lunch Dominik Schneble talked to us about his BEC lab. Bose-Einstein Condesate. A BEC occurs when you supercool a gas, in this case rubidium, and as the particles cool their wave like nature gets more spread out leading to us not being able to discern one molecule/atom from another. So basically it becomes like a soup. We then got to tour the lab itself! It was cool to see the actual equipment ater being told about the set-up. ## July 15, 2014I've been dissecting the white light interferometry set up from the paper mentioned on my ideas page. The CMOS camera the lab has unfortunately didn't come with a lens, and the ThorLab website seems to support that claim. Dr. Noe, Melia, and I later ate lunch together at the Simons Center. I got a portebello mushroom and it was delicious. When we got back to the lab I set out to get the CMOS camera up'n running. Downloading the software from online was relatively painless but finding a lens to fit the camera was slightly more difficult. Dr. Noe eventually found a 50mm lens that attaches well to the device.
Picture of a dime taken with ThorLab CCD cameraIt has a pretty good resolution and with a bit depth of 8 bits. I hope to learn more about the properties and capablities of this camera as time goes on. Specs of DCC1545M. camera. See Melia's page on the differences between a CCD camera and a CMOS camera: link. ## July 14, 2014Today we had another meeting in the conference room to discuss project ideas. It seems like I've gravitated to more of a biology approach to physics though I'm not really sure why. I also really like looking into the instruments used to gather data from our body and unseen events such as sound waves. Later I read articles in Applied Optics journals. Three articles that seemed very interesting and could possibly produce a project were using a simple method to measure the Mueller matrix, using white-light interferometry to calculate the dispersion measurements of water, and an improved Ronchi tester. The improved Ronchi tester sand white-light interferometry sound doable, while the Mueller matrix not so much because it uses liquid-crystal variable retarders. ## July 11, 2014This morning we went to an AMO seminar. The talk was given by a engineer from the SAES group abut NEG pumps which they are selling. Otherwise I have been looking into biomedical applications of optics, such as a pulse oximeter which we talked about yesterday at a mini-group meeting. Coincidentally, later that night I heard about an app that can measure your pulse rate by looking at the color fluctuations in your finger. This spurred me to look at other medical apps for Iphones and thought about making my own app. One idea would be to create an app that measures pupil dilation/size for you by utilizing the phones built in camera and LED light. Another far fetched idea was to redesign a pulse oximeter so that it was small enough to fit onto someones finger tip, kind of like a fake nail. The device would have bluetooth or wi-fi capabilities so that it can transfer data to a computer program or app. ## July 10, 2014Today we did an estimation or Fermi problem for finding the focal length of the lens inside a camera from a picture of a tennis match. By using simple geometry we were able to create the equation:
where w To understand hyperspectral imaging, I started looking into spectroscopy and the different projects done in the LTC with it. The majority of projects done in the lab have used rubidium because it has a simpler spectra due to the elements single valence electron. Past work at LTC for Spectroscopy: ## July 9, 2014We had our second pizza lunch today! Before it we had a nice discussion with Metcalf about laser cooling which is a topic that Ikaasa has expressed an interest in. I really enjoyed the talk Taylor, a masters student here at SBU, gave about HIP or hyperspectral imaging technology. I got to talk to him and his mentor about a paper I had read about the optical properties of skin in the near infrared wavelengths, and they told me about Accuvein, a technology that uses infrared imaging to map out where veins are located in real time and then project back an image of the veins. After the talk, I looked more into hyperspectral imaging. Hyperspectral imaging can be used in many fields to figure out the composition of various things. In agriculture, you can tell what plants are healthy and which are dying just by taking a spectral image of the field. On the other hand, we can also use it for chemical imaging which could aid our soldiers at war when exposed to harmful gases. ## July 8, 2014Today I had the opportunity to help out the freshman orientation for WISE students here at Stony Brook. The day started off with a Q&A panel in the morning and finished with registration in the afternoon. I's excited that the WISE program has grown so much over the past ten years and each year the program just gets more diverse. I fortunately was able to make it back to the lab for a short while to have a discussion about resonance. Resonance itself is when an object vibrates at its natural frequency which is set by the shape and material of said object. This can be induced when one object is vibrating at the same natural frequency as another thus forcing the second object to vibrate. Resonance is at play in many things such as musical instruments and RLC circuits.
## July 7, 2014We started today off by talking about the golden ratio(1.618..) and how to find it from the fact that the ratio of two line segments is equal to the ratio of the segments added together with the longer segment. This golden ratio can be related to the Fibonacci sequence because as the sequence progresses the ratio of adjacent terms gets closer and closer to the 1.618. The Fibonacci sequence in general is very fascinating because of its presence in nature, for example pineapples follow the fibonacci sequence After talking leaving the whiteboard I remembered seeing an article online about Fibonacci zone plates. Zone plates in general use Fresnel diffraction to focus light. Fraunhofer and Fresnel diffraction are often confused with one another. Fraunhofer diffraction is when we can assume the light approaching the diffracting object is parallel and monochromatic while Fresnel diffraction when we can't make these assumptions.
## July 3,2014In the morning I spent my time finishing the article I was reading yesterday about the optical properties of skin. I also looked more into integrated spheres and how you can make one of your own out of styrofoam.
## July 2,2014Today was the first pizza meeting! Everyone in the LTC group gave presentations about their past research experiences. The pizza was delicious too! There wasn't many people in attendance but hopefully other Wednesdays have better. In the afternoon I started reading a paper on the optical properties of skin in the near infrared wavelengths. They used a double integrating sphere system to capture the scattering effects of the skin samples. About halfway through the paper, Dr. Noe asked me to help with setting up webpages and teaching everyone the fundamentals of how they work. We had some issues in the beginning but by the end of the day everyone had the hang of how the server and webpages work. That night I got to eat dinner with some other WISE girls who are doing research on campus. It was nice to see some familiar faces and talk about how everyone's summer has been!
## July 1,2014Today was spent working our presentations, and I got the chance to edit my webpage. I also looked at a few OPN magazines and ran into a few topics that I would like to look into more. One of which is the idea to use artificial muscles to create diffraction gratings that can be manipulated to harness all the colors the human eye can see. Another topic I found was 3D imaging at a distance which used a near-infrared laser and a single-photon detector to build a 3D imaging system. It works up to 1 km but has difficulty due to the optical properties of the skin in the near-infrared range.
## June 30, 2014Today was the first official day in the lab for the summer and I am thankful for the opportunity to return and work here this summer! In the morning, I met the high schoolers who will be working in the lab and Melia. In the lab we spent the morning talking about the pig toy and how we can tell that it is parabolic. We can tell its parabolic by measuring its curve and by how it reflects the light inside of it. Next we had a delicious lunch at the Simons Center which was followed by going outside and burning pieces of paper with magnify glasses!
After lunch we talked about the small angle approximation and the troubling problem I encountered last semester when we used the approximation to estimate the change in length of the hypotenuse of a triangle. Our afternoon was topped off with demonstrations of the labs interferometer and using a magnify glass to focus an image of a light on the whiteboard. Today was filled with so much information it's hard to even remember everything we did! But overall it was a great introduction to working in the LTC again!
## Spring 2014
## May 4, 2014Last Wednesday, we had the privilege to present our posters at URECA. It was a lot of fun. People were amazed by the pig mirage toy, some even made their friends come over to see it because they enjoyed it so much. Besides siting at the table showing people different objects and toys from the LTC, we got to walk around and see everyone else's projects. It was nice to see all the different kinds of research being done here at Stony Brook by undergrads and it amazed me that so many people are involved in undergrad research.
## April 14, 2014The past couple of weeks have been busy trying to figure out what exactlly our projects are going to be and writing our URECA abstracts about them. My final abstract can be seen here. My project isn't really about cloaking anymore but is more general about different optical tricks that change objects or make them disappear. Having it more general and sort of vague let's us explore a variety of things and doesn't define the project to a specific topic. I kind of wanted a more spefic challenging project but I think this project will help me understand the fundamentals of optics in a more fun way. And I'm sure there will be unseen challenegs along the way.
## April 4, 2013Today we finally decided on our projects! I'm doing a project about optical cloaking which you can see more about on my ideas page. The ideas I could do for it are uni-directional meaning the cloaking effect only works from one angle or direction. I would make a table top verison of either the Snell's Law Cloaking example or the one using mirrors shown here. I kinda want to put my own spin on it but not quite sure what as of right now...I guess we'll see what I can imagine up! ## March 28, 2014Today, we showed a prospective student, Emily, around the LTC and campus. We ended up eating at the Simons Center for lunch and it was fabulous, I had never eaten there before! During our meeting we talked about various different ideas we could do for our projects some of which you can see here. I am very interested in the Lissajous Figure one and the optical cloaking one as well.
## March 15, 2014I was outside today with my family and happened to be wearing brand new sunglasses. I guess they were polarized because when I looked up at the sky I could see iridescence on the sides of the clouds near where the sun was being covered. It was very exciting to me to see something I had briefly looked at online about atmospheric optics. My parents did not share my same enthusiasm as I attempted to take pictures of it through my sun glasses but I think they enjoyed seeing me excited about something or nerding out as my sister would call it. Sadly my pictures did not come out very well, maybe I should look into finding a polarized lense or think of a better way of taking pictures. I also told them about the moon illusion, where we think that the moon is actually bigger near the horizon but its not and scientists have no idea why our brain thinks that it is, and no one believed me. "The good thing about science is that its true whether or not you believe in it." -Neil Degrasse Tyson
## π-day 2014Today was Pi day! I could not find any pie on campus so I instead looked up math jokes on the internet while giggling to myself. Earlier in the week, we talked about the Law of Malus. The Law of Malus states that when a polarized beam of light is shown through a perfect polarizer the intensity of the light that passes through the polarizer is related by the function I=I_0 cos^2(theta), where I_o is the initial intensity and theta is the angle between the lights initial polarization direction and the axis of the polarizer. The intensity of the light transmitted is equal to a cos^2(theta) graph which looks a lot like a regular cosine graph. Now that is only when the light is sent through one polarizer, when it is sent through two we get the equation I=I_0cos^4(theta). Whenever we add a polarizer, we can alter the equation by increasing cosines exponent by two. The intensity of light when shown through two polarizers results in a slightly different graph than before. Instead of being curved at both ends, the cos^4 graph tends to flatten out more as it reaches 0 intensity which means the intensity of the light going through decreases slower as it gets close to 0 intensity.
## February 28, 2014Today we talked more about applications of the small angle theorem, using the series of the sine and cosine functions to find the series for the tangent function, and ended with a demonstration of a laser setup in the lab. We started out of discussion by talking about trig series and trying figure out the approximation of the tangent function. As we were doing our derivation, we needed to multiply our cosine series and sine series by some value so as to simplify our answer. This turned out to be the complex conjugate of the cosine series! The complex conjugate we learned is used to rid the denominator of imaginary or complex variables and is equal to the opposite value of the complex variable e.g. if we have (c+id) then its conjugate is (c-id). We ultimately figured out that tan(theta) is approximately equal to (theta+theta^3/3+) We came about this after talking about cosine or quadratic error.We then moved on to cosine error. Cosine error relates to the error that can occur by measuring the distance to something by taking a point above where youre measuring, getting that distance, and then using the angle it is to the axis with the cosine function to find the wanted distance. Dr.Noe then drew us a diagram that I want to put in later but basically showed a triangle with one horizontal length L, a vertical length y, and a line connecting them labeled L+delta and asked us ways that we could determine delta. I suggest that we could use the cosine and sine functions to determine it and by using the small angle approximation let sine(theta)=theta. Our derivation this way can be shown below. The only problem with our result was that our delta value ended up being negative which it shouldnt be. The usual way of doing this is by using the Pythagorean Theorem along with the binomial expansion. Sam then gave us a talk about the Doppler Effect/Shift and how it can be related to astronomy. It was very interesting to see the real world application of something we had learned about in class. Then Natalie started to talk about how we see colors and about the electromagnetic spectrum, but soon we went off on tangents after Dr.Noe asked us questions like Whats an octave? Whats the frequency of a cell phone? and How big is a red blood cell. His questions stumped us at times and made us realized that its important to know the general scale of things in the universe. Dr. Noe then showed us a laser set up in lab that shows an example of the Doppler shift that Sam talked about. The laser ended up getting split at some point and then projected onto the wall creating a grating similar to that of Youngs experiment. One of the mirrors was pulled by a rubber band, the grating moved with a velocity left or right. This was due to the beams traveling different distances and thus being at different stages of in or out of phase. Another example of this that he showed us was with tuning forks. When the tuning forks were at slightly different frequencies, a beat would form which I recognized learning about from my PHY131 last semester. We ended our meeting by Dr. Noe telling us about a tiling problem which I hope to write more about later. |