What the HECK!

[Things]

I dont know how many of you have seen this thread over at LPF, but its worth checking out, crazy stuff!
http://www.laserpointerforums.com/fo...m=1229287299/0

Basically, he has a red diode from a 16x DVD burner, and burns plastic at the focal point. when he moves the plastic away, there is little tiny balls or red light left right in the focal spot. I dont think it is smoke, since you can even MOVE the laser, and they dont go away!

Any one here got any sort of explanation for this? Surely such a low power couldnt ionize air, and I thought ionization was blue?!?!

[drlava]

This is cool, it could be used for a lower laser power 3D display along with the right fog that lowers the plasma threshold.

[mixedgas]

yeah I can explain it. Its optical trapping of dust particles at the beam waist. The high electromagnetic field at the crossover point causes very tiny charged dust particles to be pushed into the core of the beam.

no plasma, just dust scattering the light.

Its a well known thing. Usually doesn't occur in air like that, but I've seen laser beams at 2-3 watts drag in dog hairs on my projector into the center of the beam.

There is a very tiny ceramic dust, carbon soot, or something else reinforcing the plastic, and its drawn into the beam after the combustion and held there,

1. hard to reproduce
2. wont happen with just any laser
3. right place at the right time with the right material sort of thing.
4. usually needs more then 1 beam.
5.remember the light field just flows around objects any shorter then say a wavelength, hence the trapping.
6. works best with lower powers.

This is mundane in the scientific community, its used all the time to trap bacteria and other small objects in front of microscope objectives.

google "optical trapping"


"NOW YOU KNOW THE REST OF THE STORY," A quote from Tom Harvey.

Steve

PS , please go tell the pointer guys this before it ends up as support for numerous conspiracy theories.

[drlava]

Oh yes, optical tweezers are used in cell manipulation in the lab quite a bit. The tight beam focal cone must help to confine the particles along the beam axial direction. Good one Steve!

[DZ]

Thats a very neat effect! Just tried it with my 405nm pointer and it worked!

[DZ]

Well it works with my 405nm laser, which is only about 75mW and my 660nm which is about the same power. I managed to get one to last with the 660nm laser for about 30 seconds. I've tried a couple different things, but the best result I had was with the tip of a sharpie.

[Artix]

^ I just made a video of it! It looks awesome!

http://ca.youtube.com/watch?v=R6gkXkHzIsM

[Things]

Everyone seems to be using some kind of pen. i'll go grab a pen and try it out again.

EDIT: It just worked!

I'll try to film it, but it sure is freakin cool!

[mixedgas]

real optical trapping:

http://ca.youtube.com/watch?v=jCdnBmQZ6_s


I'm impressed.

Steve

[dream beamz]

real optical trapping:
http://ca.youtube.com/watch?v=jCdnBmQZ6_s
I'm impressed.
Steve

Bad ass, cant do that with any hobby materials