24th October 2005 - 10:59 AM
Hi Pr0pensity and Denison06379,
I "think" you may have created a "dislocation" and excited some high order orbital angular momentum modes in light with that "edge". This phenomenon is usually called "Twisted Light". It is an interesting "diversion" and it has some strange properties. For instance you can cause small objects to spin with it and you can use this as "optical tweezers" under the right conditions. I am unsure this is what you have but it "looks" like you may have it there in some form.
Here is a grating that surely will excite orbital optical angular momentum...
It you create this image at the right scale on a good "photocopier" on OHP film, with a decent CW laser, you will be able to create those vortices shown here...Light Beams in High-Order ModesHomemade Vortices - Generating your Own Doughnuts!Geometric Phase Associated with Mode Transformations
These suckers can exert forces transverse to the direction of propagation and "grasp" stuff and "spin" them etc. that is if they are small enough. They are more useful if they are small...
Now that you may have a handle on this you may be able to get this to be useful... yours certainly looks a bit different. The important bit about this is to aim the laser at the "dislocation" at the center. There are other gratings with a three pronged fork at the center. I "think" we are dealing with "optical berry phase".
There is an associated "Parallel Transport" Java Applet that shows some interesting effects of parallel transport of vectors on a surface of a sphere...Spherical Geometry DemoTwisted Light Communication