Comments on: How To Build a Laser Tractor Beam (in Theory) http://blogs.discovermagazine.com/80beats/2011/03/03/how-to-build-a-laser-tractor-beam-in-theory/ 80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles covering the day's most compelling topics. Wed, 23 May 2012 16:07:28 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Matt B. http://blogs.discovermagazine.com/80beats/2011/03/03/how-to-build-a-laser-tractor-beam-in-theory/comment-page-1/#comment-747007 Matt B. Mon, 28 Mar 2011 16:28:33 +0000 http://blogs.discovermagazine.com/80beats/?p=26988#comment-747007 You would also get a tractor effect by shining light at the edges of a lens that refracts it straight away from the light source. The momentum vector of the light before it hits the lens is reduced by the fact that all of it is moving at an angle from the overall direction, but then the lens focuses it so that it's all in parallel to the overall direction, increasing the magnitude of the light's momentum away from the source. The difference goes into the lens, which therefore gains momentum toward the light source. There might be something you could do along these lines with diffraction to get a broader set of applications. You would also get a tractor effect by shining light at the edges of a lens that refracts it straight away from the light source. The momentum vector of the light before it hits the lens is reduced by the fact that all of it is moving at an angle from the overall direction, but then the lens focuses it so that it’s all in parallel to the overall direction, increasing the magnitude of the light’s momentum away from the source. The difference goes into the lens, which therefore gains momentum toward the light source.

There might be something you could do along these lines with diffraction to get a broader set of applications.

]]> By: John http://blogs.discovermagazine.com/80beats/2011/03/03/how-to-build-a-laser-tractor-beam-in-theory/comment-page-1/#comment-680856 John Fri, 04 Mar 2011 17:23:19 +0000 http://blogs.discovermagazine.com/80beats/?p=26988#comment-680856 While I do appreciate the novelty of using a Bessel Beam for backward propagation, it seems only a natural progression given the expansive range of techniques that optical tweezing has evolved! Some laboratories use holographic techniques to manipulate multiple particles at once as well as those that use polarized light to spin particles. While I do appreciate the novelty of using a Bessel Beam for backward propagation, it seems only a natural progression given the expansive range of techniques that optical tweezing has evolved! Some laboratories use holographic techniques to manipulate multiple particles at once as well as those that use polarized light to spin particles.

]]>