July 9, 2002
I have finally decided to start my journal. Currently I'm not exactly sure what I'm going to research yet. I have been doing a considerable amount of reading on optics, quantum mechanics, lasers, and Linux. These are all important to whatever research I do and probably help me out in the future (knowing linux is very useful). After many hours reading, taking notes, and browsing through the Laser Links posted on this site, I have come down to about four main areas of interest. The first is Holography; perhaps a project using holographic imaging to study acoustical wave patterns of instruments. The second is Sonoluminescence, the process from converting sound to light. I found sonoluminescence very interesting, mainly due to its potential to play a large part in future methods of energy production. The third is light diffusion, which would probably be a good study considering the numerous resources in the laser teaching center. The fourth is something with the violin called VIAS. Supposedly its a way of measuring the resonance pattern of the violin and can be used to aid the construction of a violin and the positioning of certain pieces for optimal performance. Sounds interesting, but I'll have to read more into it to fully understand.
July 11, 2002
I'm still not sure what my project will exactly be yet,
but I've narrowed down my ideas a little. Currently I'm very interested in
sonoluminescence, I've done a lot of reading about it and have posted many weblinks in
my Websites page. If
I study sonoluminescence, I may study the effects of a magnetic field may affect the
light produced (that is, if I can get the light to shine in the first place). Also,
the study of SBSL (single bubble sonoluminescence) with different gases and lquid
mediums seem to be very interesting. I'm thinking of using lasers as a way of
measuring the bubbles through Mie Scattering and perhaps see any effects lasers may
have in the process of sonoluminescence.
Another topic I've been looking into is
light diffusion and light scattering. Today, I pretty much spent the entire time
looking through the textbook and learned about the various scatterings of light, such
as Rayleigh Scattering, and the effects of different mediums on light. On one of the
links on my websites, The
Diffusing Light Website they go in to some detail about the behavior of light
through foam mediums and the more intriguing granular substances, such as sand.
July 15, 2002
Well it seems that I'm not going to be able to come to
the lab after the Simons Fellowship is over, thus I need to start a project very soon
so I can get the most research and experimentation as possible. My prime interest
seems to be a study in sonoluminescence. I can use lasers through Mie Scattering and
hopefully I'll be able to get the bubbles the light up. I might try to use different
gases and mediums and study the effects of each, possibly use a magnetic field too and
see if any of the properties of the bubbles change.
July 16, 2002
Today I talked with Dr. Noe about my project, and
luckily, I will be able to commute to the LTC on weekends even after Simons. I'm
rather sure that my research will definitely be in region of the relationship between
sound and light. It's just that sound/light relationships strike a chord with my
interests, I'm not too sure why, maybe it's my affinity to music, but I definitely
know that it interests me. Sonoluminescence, as I've previously explain, is one of the
possibilities, and after reading sections of the Phontonics book, I've studied a good
deal about acousto-optics and how it deals with sound/light relationship. I've also
looked into sonochemistry, using ultrasound to produce light and images, to try to
fully understand sonoluminescence because both are interrelated. Also, another thing
that really grabbed my attention to sound/light relationships was when Dr. Noe and
Owen weere clapping and singing to the HeNe laser. There were some changes in the
modes of the laser, and the light started to behave differently to the sound. That's
an interesting idea for an experiment as well.
July 17, 2002
Sam Goldwasser came in today. He gave a very
interesting talk about being an electrical engineer and his experiences with lasers.
Here is his website, Sam's Laser
July 24, 2002
Last week when Dr. Noe and I talked about potential project ideas, liquid crystals came up as a topic. I've looked into the field and found the properties of liquid crystals to be quite interesting. A liquid crystal is a fluid like a liquid but is anisotropic in its optical and electro-magnetic characteristics like a solid. When the liquid crystal is formed from the isotropic state some amount of positional or orientational order is gained. There are two different types of liquid crystals worth noting; Nematic and Smectic. Both types can become chiral; not symmetric when reflected. Liquid crystals, as I had already been aware of, are used in certain flatscreen computer monitors, calculators, and other displays. The light emitted from the LCD are polarized, thus, at some angles, the displays cannot be clearly viewed and a negative image can occur. Potential project idea could be a study of liquid crystal optical properties, and possibly a way to improve the angle of light propagation. Another idea that came to mind was the study of acoustical properties of liquid crystal, for as discovered by Jay Patel, liquid crystals do have acoustic properties. Perhaps I could do a Fourier transform of the liquid crystals to analyze the sound waves. I'm not sure what the implications are for liquid crystals and sound, however one article proposed the potential of micro speakers or delay circuits.
July 31, 2002
Today I tested the resonances of the flask. Most notable amplitude changes occured betwee 38.8kHz and 39.3kHz. However, after shifting around the apparatus, the largest variation occurred between 38kHz and 40kHz. At first using the oscilloscope, Dr. Noe showed me the Agilent Voltmeter. This is a very handy device for it can display the V-rms electronically, as opposed to the oscilloscope, from which I would have to calculate from the graph produced. Anyways, when gathering data, I noticed there is a considerable amount of mechanical vibration caught on the microphone as well the outlet's own 60Hz pickup. Also, with slight movements and changes to microphone wire position.
The data shows similarity in the width of the crests, and I'll be comparing them to data of more thoroughly degassed water to see whether the resonances change. (accepted is around 25-26kHz).
August 2, 2002
After setting up the sonoluminescence apparatus again, I degassed the water. I did this by connecting the pump to the flask and filled the pump chamber area with liquid nitrogen. Slowly, the water was degassed as the pressure decreased. The resonances dropped from 38.8-39.3 kHz to 35.4-36.6 kHz. Although a drop in the resonances was normal, I expected the resonances to drop to a much lower point, around the 26 kHz mark. After resonance points were checked, I connected the power sources to the amplifier and the frequency generator. The entire apparatus was not set up and ready for sonoluminescence. First, I started capturing bubbles. I did this by finding the resonance point. This point was at 26.1kHz to 26.6kHz, much more satisfactory to my predictions and to what other researchers got as their predictions. Here is a graph of the resonance.
As compared to the pre-degassing w/o current, the amplitude reached a much higher point, peaking at around 223 mV-rms. After getting these data points, I began to "catch" bubbles. By using a pipette, I would suck up just a little bit of water and squirt it back to the flask, introducing air bubbles to the system. The bubbles gathered to the middle and formed a very tiny bubble (according to Putterman, no larger than 50 microns in diameter.) Upon close observations, it's apparent the bubble is vibrating rather quickly in its place. I have not yet been able to achieve sonoluminescence, however, I am getting closer.
August 5, 2002
Today I actually got the bubble to light up! It took quite a bit of trial and error. At first I was trying to get sonoluminescence at 1V amplitude from the frequency generator, but that was too weak. So, I switched it to 4V and started hearing a fizzy noise from the cavitation. I could also hear high pitched ringing, so something is causing the original frequency to be lowered. Looking at the oscilloscope, the trace was very rigid at the top and bottom, noting that there were bubbles caught. After completely darkening the room and putting a black box around the apparatus, I began toying with the frequency. At around 26.620 kHz, sonoluminescence occured. After further testing, the phenomenon occured most frequently from 26.620-26.670 kHz. However, the light was not stable. It would flicker and go out and come back on again when there is no influence on the system. I think that there is a little too much air back in the water and that I should degas it again soon. I also would like to try using cold water, for it supposedly makes sonoluminescence brighter. I am very pleased with the light, as it is a tricky to produce it. I hope to analyze the light with a photomultiplier and perhaps use mie scattering to measure the size of the bubble. An idea that interests me is to determine whether or not the light is polarized or not. I think a study of the properties of light and its relation and perhaps determine a function for its brightness and/or stability.
August 12, 2002
A few days ago, I had experimented further with sonoluminescence. Since the light was very unstable, I decided to degas the water once again. In addition, I also chilled the water (refrigeration). The result was a much more stable and brighter light during sonoluminescence. Since as the water heated back to room temperature, and the light remain stable, I don't attribute temperature to stability. However, it DID get dimmer. Thus, I attribute the intensity of light to the temperature of the medium, also, the as the light became more intense, it seemed that the amplitude increased as well. As each day went by, the sonoluminescence became increasingly more unstable, which I can attribute to the gas content of the water. I'll probably need to degas the water again and plan to use the photomultiplier and CCD camera to analyze the light and take pictures.
August 16, 2002
I got pictures of sonoluminescence! Thanks to the use of a CCD camera, with a exposure time of 2 secs, I was able to get images of the sonoluminescent bubble, quite clearly. Since I used the colder water again, the light was especially bright. The water was also freshly degassed, so the light was very stable, lasting for several minutes at a time. As I increased frequency/amplitude, the bubble became brighter. I was able to capture this relationship by taking pictures at different frequencies and amplitudes. I also saw that as the inductance voltage increased, the bubble also became brighter and increased in size. I am very happy with my results and hope to use the photomultiplier soon.
September 21, 2002
Research went very well Saturday, I recorded a good amount of data with the digital oscilloscope program, and was even able to use the photomultiplier to measure the intensity of the light. Another thing I was able to do was see the effects of glycerin. I put in 5mL of glycerin in the water and then mixed and degassed the solution. I was able to reproduce sonoluminescence, there was little difference in the intensity of the light, but the light seem very stable for a long period of time.
October 5, 2002
Today was a little slow in terms of sonoluminescence, however I notice a few things. Before I had realized that glycerin had made the glow a bit more a consistent and that the use of cold water increases brightness. When looking at the resonances of water with glycerin, the amplitude ranges from 5 v-rms - 11 v-rms. With cold water, it was 12 V-rms - 26 V-rms, and as time passed, it the range decreased. By the time the water was at room temp the resonance amplitude was only 2 V-rms - 6 V-rms. With colder water there are no as many harmonics present as there are in room temperature water or water with glycerin. I also I attribute this to gas content increase as well. I'll probably do a lot of reading on harmonics and more in depth research on wave behavior from the email Dr. Noe sent me to make more sense of my observations.
October 19, 2002