Optical Trapping Pictures

[nospin]

I got this it to work!

The SF-AW210 at 263mw works better than the LOC Red at 300mw
I'm guessing because the violet burns better and makes more smoke
then the red?
I have had maybe 8 or more particles trapped a few times for a very short duration! 1 or 2 is more common.
Quality of the lens and a very short focal length are key to success
with my 405 Jayrob lens a 1" FL seems to work the best
and the black sharpie tip is the only thing that's worked so far
Some pics are of them forming and bouncing off each other while
others show them stable. and the sharpie tip gives some perspective.
Canon S5 super macro manual focus 1/8 second

Jim

 

[kevinmassey]

Those are some awesome pics! I'm gonna have to try this again with my PHR.

 

[laserboystuart]

nice pics :gj:

stuart

 

[Things]

Yeah, optical trapping is a really cool effect.

 

[MrRay]

Very Cool, whats the best way to do this?

 

[laserboystuart]

Very Cool, whats the best way to do this?

focus your laser up very close from the lens (better to do this with jayrobs or larryDFW's high power lenses as they have a shorter focal length when compared to aixiz acrylic) and while focused very close put a black object in front of it like a sharpie marker, wait until its smoking a lot, remove the pen and you should see a couple of little particles floating in the air.

stuart

 

[MrRay]

will try this lol. looks pretty legit

 

[Benm]

It's legit alright, but the sharpies seem almost crucial to get it right. I've tried it with several different materials (various plastics, incense, cardboard etc) and nothing seems to give off particles that get trapped reliably.

 

[Ash]

Wow. Never heard of optical trapping.:tinfoil:
Very cool use of the electric field at the focus of a laser. Is +300mW necessary? Can it be done with lower powers ~100mW?
"The narrowest point of the focused beam, known as the beam waist, contains a very strong electric field gradient. It turns out that dielectric particles are attracted along the gradient to the region of strongest electric field, which is the center of the beam." Source: Optical tweezers - Wikipedia, the free encyclopedia
I think in order to control any dielectric particles that you trap, you need a system with a microscope and camera set up. :thinking:
They are pretty expensive for a kit. Thor Labs
OTKB - Optical Trapping Kit - Essentials -- - $16,400.00

 

[toogoofy]

This is really cool :wave:
its fun to do with my red

 

[proud2deviate]

Also, to produce this effect, it is crucial that the air be absolutely still. Sharpies work well, but the big black chisel tip markers seem to produce the most reliable results for me.

 

[kevinmassey]

I just tried this again, and it finally worked! I was burning incence, and tried it with my PHR and it didn't work, so I got my green and tried with a telescope lens. That still didn't work, so I got another telescope lens and used it to make a tiny focal point. It worked, but only after I put a sharpie in the focal point.

 

[RA_pierce]

Great pictures. There are a few threads floating around somewhere about this.

I think optical trapping works best with lower power.
I have done this successfully with 200mW red and 150mW violet, and a couple times with 100mW green.
Higher power lasers just seem to obliterate anything that comes near the focal point... the vapor shoots out so fast, I don't think any particles will be able to get stuck in the beam.

310mW Red... sometimes.
480mW Violet... nope.
700mW Green... nope.

The air must be very still for best results.

When photographing this, use a flat black background that will not interfere with the image. Also, if your camera is capable, focus it manually on the laser's beam.