US 12,405,409 B2
Chemical diffusion treated volume holograms and methods for making the same
Austin Lane, Sammamish, WA (US); Marvin Dion Alim, Duvall, WA (US); Yang Yang, Redmond, WA (US); and Janee Ashley McNeil, Seattle, WA (US)
Assigned to Meta Platforms Technologies, LLC, Menlo Park, CA (US)
Filed by META PLATFORMS TECHNOLOGIES, LLC, Menlo Park, CA (US)
Filed on Oct. 21, 2021, as Appl. No. 17/507,517.
Claims priority of provisional application 63/114,226, filed on Nov. 16, 2020.
Prior Publication US 2022/0155503 A1, May 19, 2022
Int. Cl. G02B 5/18 (2006.01); G02B 5/32 (2006.01); G03H 1/02 (2006.01)
CPC G02B 5/1857 (2013.01) [G02B 5/32 (2013.01); G03H 1/0248 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method, comprising:
making an optical grating having a non-uniform refractive index profile along a direction substantially perpendicular to a plane defined by the optical grating, including placing a layer of photopolymerization material having a first surface and a second surface that is opposite to the first surface between a first material transfer layer and a second material transfer layer so that the first surface of the layer of photopolymerization material is in contact with the first material transfer layer and the second surface of the layer of photopolymerization material is in contact with the second material transfer layer to allow material transfer between the layer of photopolymerization material and the first and second material transfer layers by diffusion;
removing the first material transfer layer and the second material transfer layer from the layer of photopolymerization material; and
exposing the layer of photopolymerization material to two beams after removing the first material transfer layer and the second material transfer layer from the layer of photopolymerization material.