I’ve disappeared for the past few weeks because of the insane amount of work I’ve had. However, in addition to all of the schoolwork, I have also been able to feed my newfound passion for lasers.
It all started with the “5mW” greenie I bought. Soon after, I purchased another 5mW green laser and a red laser as well. I immediately noticed the difference between the two green lasers; one had a far brighter dot than the other.
Soon after, I discovered LaserPointerForums.com and eventually decided that I would build a Blu-Ray laser. Using diodes extracted from Blu-Ray and HD DVD players, laser enthusiasts design laser pointers based on small LED flashlights and other similar housings. The coolest thing about these pointers is that since they operate at wavelengths very close to ultraviolet light (typically about 405nm), they fluouresce objects. So, if you’re pointing the laser at a white screen, you may not see the dot clearly, but the screen itself will fluouresce. The uranium vaseline glass marbles that I bought will glow brightly. Furthermore, the laser will also burn pretty much anything when pumped up to about 100mW.
These pointers basically consist of 4 components: the laser diode mounted in a focusing module, the driver (a device used to regulate current and voltage output to protect the diode), and the battery. Blu-Ray diodes typically require about 5V to lase. The PHR-803T diode (currently the most common one available) requires fairly low currents. Most people report that the diode is stable at 100mW, which requires about 125mA of current (see this sketch).
Anyways, while researching different build methods, I came across the website of Colin Joye, who had been working on a Blu-Ray laser based on the KES-400A diode for the PlayStation 3. It was about 3 minutes before I realized that the site was hosted on the MIT servers; as it turns out, Colin was a recent grad student who was finishing up his dissertation. Colin showed me a laser calorimeter he had in his lab and I tested my 3 existing lasers. The first green reported 55mW of combined Green and IR power. The second reported about 20 and the red reported about 20 as well. The 55mW was quite a shocker; no wonder the beam is visible and it can cut through electrical tape easily.
After playing around with the calorimeter, we the began to discuss building a Blu-Ray laser from scratch. I’m designing some models in Autodesk Inventor (which is free for anyone with a .edu email account!) that will provide us with a housing that will carry the diode, the driver, and a CR123A battery.
I’ll post pictures once we are able to get some working products. Hopefully, we’ll have something soon!
