Monday, January 09, 2006

Christmas Break Senior Project Progress

Happy Holidays!

The following is a summary of the main tasks and project progress completed over the break:

- Following coversation with Colorlink Engineering Gary Sharp I spoke with John Korah again. After several back and forth coversations, we discoverd that for the particular application required in my project, the Colorlink LC modulator would not be sufficient. The modulator is a non-linear component, and its retardance level is based on a preset input voltage based off a device characterization table. This would make interfacing the device with the experiement extremely difficult as smooth sinusoidal (analog or fast digital) operatation is essential. Unfortunatley, a good amount of time was spent communicating and planning with Colorlink before this discovery was made. A ColorLink engineer I spoke with recommended looking at a spatial light modulator as a possible solution, and was refered to the vendor DisplayTech.

- DisplayTech's spatial light modulator (SLM) was investigated as a possible solution to achieve sinusoidal intensity modulation without using an expensive electro-optical modulator system (well over $10k). However, upon investigation of the product and corresponence with Dr. Blair, it was found that the SLM offered by Display Tech was a multi-pixel modulation device, and although would work sufficiently for my application, was somewhat of an overkill, as only one large pixel was needed to modulate. Whlie a possible solution, it was determined that a better less expensive method could be used. Product information for this SLM is located at the link below:

- At Dr. Blair's prompting, I investigated extensively the use of variable optical shutters in analog modulation. I contacted Kelly Gregorak of Boulder Nonlinear Systems and found information regarding their TS and XT optical shutters. A link to their product information website is included below. The TS shutter offered by BNS seemed ideal, however the driver required must be at least 100V, and if a cheap driver does not exist, a a regular e-o modulator is just as reasonable a solution despite the price. The XT shutter however can use a 20V driver and can operate around 200Hz (which should be sufficient - this will be investigated early in the week of 1 - 09 -06). If BNS can identify a cheap driver, the TS will be used, however if one is not available and the modulation frequencies will work for slow and fast light propagation, the XT shutter will be utilized.

- The majority of the break was spent further investigating exisiting solutions to the problem of achieving the neccessary modulation working around cost effective technologies. This proved a fairly formidable task (much more so than I had assumed) however, it appears now that a reasonable solution has been found that fits the necessary specifications and pricing. This task was further complicated by working around the schedules of sales and engineering representatives at vendor companies and their holiday plans. Overall though, I feel that the project has made a significant and necessary step ahead, and with further work, the main goals of creating a robust and operating experiement setup will be near completion soon, allowing time for preparing the experiment for exhibition.

- A link to the main reference for the expermental conditions necessary to achieve slow an superluminal propagation in room temperature Alexandrite crystal is below:


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