Re: It Was a Good Day in Laser Land...
I first saw it mentioned in a thread around here and searched all i could. IIRC, it is supposed to demonstrate how the unique properties of lasers allow lights ability to exert pressure to trap, or even move particles. I've trapped one, and moved the laser and it would move with the beam. I've also seen vids were turning the focus moved the particle up or down the beam.
I've seen theories on here that it's small carbon particles getting trapped, being able to take the heat.
They only get trapped in the focal point. One analogy that I saw that made sence was comparing it to gravitational lagrange points. Except with a laser, it's optical pressure "pushing" anything after the point and "pulling" anything behind it. If the particle is in just the right spot, it is balanced by the the push from a narrowing beam and the pull of the widening beam.
I've seen different methods of using lasers as tractor beams. The problem is thier limited to very small particles, and of course damage the goods. A few threads on here that i dug out is were i found out how to do it with 200 - 400mW laser, uaually red or 405. I used both of my 650nm ~300mW builds and a sharpie. You want to focus it so the focal point is as close to the laser as possible, about 2-3in is best, but i've done it with the focal point out to ~5in. Then insert sharpie, move back and forth a little to find the sweet spot.
I could be off, but thats the jist as i understand it. Sorry i rambled. :tinfoil: