Patent ID: 9594201
Date: 2017-03-14
CPC Classifications: B29D,G01J,G02B,G03H

Claim:
1. A method for making a volume phase holographic diffraction grating, the method comprising: placing a gelatin material between a mold and a substrate of desired curvature; pressing the mold and substrate together to press the gelatin material into a holographic medium of desired thickness and curvature; hardening the gelatin material; and holographically encoding fringes in the gelatin material such that the fringes are tilted to diffract at least some of the light that passes through the gelatin material, wherein holographically encoding the fringes includes subjecting the gelatin material to first and second expanded laser beams and using a recording lens positioned in front of the grating, wherein the first and second laser beams strike the recording lens at different angles from each other, pass through the recording lens where they interfere with each other, are diverted and dispersed, and enter the grating to create fringes with tilt angles that vary from each other.