I was searching for a Nd:YAG laser cavity for a future project when I came across a bunch of tattoo removal devices on eBay. They claimed to contain a Nd:YAG laser but at a small fraction of the cost of buying the parts separately. Skeptical, I bought one anyway since I had the option to return it if it didn't live up to the seller's claims.
Much to my surprise my unit turned out to be INSANELY powerful, so strong that it can light the air on fire! The laser head is a flashlamp pumped, qswitched Nd:YAG laser with a removable KTP frequency doubling tip for the option of green light. My estimations yield a peak output power of about 30 million watts.
In the video, I start by testing the laser against various materials, including aluminum, tungsten, coins, acrylic, and rust. Since the laser can also ignite air, I used this as a benchmark and then estimated peak power with the methods of Gaussian optics.
After destroying a bunch of stuff, I use the laser to drive another laser in a dye laser setup. Using the organic dye rhodamine B, I was able to create a beautiful orange laser by blasting the dye with green photons.
Finally, I tried giving the laser the "overclocked" treatment but my modifications destroyed the laser in one shot. oof