Smoke but no Mirrors
Optical Trapping and the Momentum of Light
The explanation talks about the wave-particle duality, but I think that’s a distraction. This is a dipole force phenomenon; the beam’s intensity is greatest at the center, and where the focal point occurs, as shown in the drawing at the end of the post. This gives rise to a gradient in the electric field. If you put a dielectric particle in this region, it will feel a force in the direction of the field maximum, or toward the highest intensity of light.
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Comments
Comment from captainpanic
Time: January 28, 2010, 7:49 am
Could it be that the bright laser light is simply screwing up the camera, leaving a dot where the bright light was before (similar in effect to what you get when you look into a bright light)?
That laser is pretty strong if it is able to cause smoke to come off that pen (or whatever it is).
Comment from Anonymous Coward
Time: January 28, 2010, 4:15 pm
Re: cap’npanic
> Could it be that the bright laser light is simply screwing up the camera, leaving a dot where the bright light was before
If you watch through past 1 minute, the experimenter does some things to demonstrate that is not the case.
I agree that there’s nuthin’ about this experiment that can’t be explained with classical physics. Maxwell talked about the energy and momentum carried by light long before any sort of corpuscular theory made the scene.
Comment from JWC
Time: February 5, 2010, 12:02 am
Hello, I am the creator of the video. swansontea has a valid point that my original description may have been a bit “distracting.” I was not clear that wave-particle duality allows us to model the same situation in different ways, with each model yielding its own interesting results.
global RSS feed.
Comment from anders
Time: January 28, 2010, 7:13 am
why does this trivially simple video have 2500 views, and my FPGA-controlled fancy real-time force-clamp with DNA tethered between the beads only has ~200 views
http://www.youtube.com/watch?v=9mVh5rMjTgY