I'm trying to develop a way to control the "exit angle" (diffraction angle) of a monochromatic light source.

For example: taking a laser; spreading the beam; and directing the light at a piece of holographic film.

...then, depending on how the original "hologram" or diffraction grating was recorded or encoded, having the light change angle or direction slightly as it is transmitted through the film.. Basically, I'm trying to create a "holographic lens" of sorts.

Is this possible? and what resources would you recommend in figuring out how to expose or record the diffraction pattern?

Thanks for any info in advanceenter image description hereenter image description here


Yes, it can certainly be done. You need to learn about the principles of holography for this really to make sense, but here's a very brief explanation of how to do it:

  • Using light from the laser, produce the beam incident from the left in your top sketch This will be your "reference beam".
  • Using light from the same laser, send beams through the film in the directions you want the light to be diffracted. This light will be incident from the same side as the reference beam.
  • Expose the film and develop it.

If you have met all the conditions needed to record a hologram (stability of all the parts of your setup to ~ 0.05 micron, all path length differences within the coherence length of your laser, and the right exposure energy and development process), the hologram will, when put back into your setup, diffract light in just the way you want.

It's not a trivial process, but it can be done.

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  • $\begingroup$ It will (of course) diffract a part of the light. The rest will be absorbed or diffracted in other directions (including the "undiffracted" part) $\endgroup$ – JTS Apr 10 '19 at 14:55
  • $\begingroup$ @S. McGrew - Thank you very much for the insight and starting point for looking into this further. If I were to divide the film into a grid, and needed each section of the grid to have a different angle of diffraction, is it possible to "print" at very high resolution the angles? from a possible Matlab type model on the pattern? Would you know of any resources I could start looking to this type of microlithography? Thanks in advance! $\endgroup$ – T Brunelle Apr 10 '19 at 15:31

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