US 12,442,961 B1
Methods of forming holographic gratings for optical systems
Yifei Wang, Sunnyvale, CA (US); Xiaoyong Fu, Fremont, CA (US); Wencong Zhu, Foster City, CA (US); Xianwei Zhao, Cupertino, CA (US); Francesco Aieta, Alameda, CA (US); Zhujun Shi, San Jose, CA (US); Hyungryul Choi, San Jose, CA (US); Zhenbin Ge, San Jose, CA (US); Shigeto Kobori, Tokyo (JP); Yoshitaka Matsui, Yokohama (JP); Yukinori Asakawa, Saitama (JP); and Jun Xie, San Jose, CA (US)
Assigned to Apple Inc., Cupertino, CA (US)
Filed by Apple Inc., Cupertino, CA (US)
Filed on May 25, 2022, as Appl. No. 17/824,791.
Claims priority of provisional application 63/225,326, filed on Jul. 23, 2021.
Int. Cl. G02B 5/18 (2006.01); C23C 16/04 (2006.01)
CPC G02B 5/1819 (2013.01) [C23C 16/042 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A method of forming a surface relief grating comprising:
depositing a first material on a substrate;
nanoimprinting the first material to form a first plurality of ridges formed from the first material; and
depositing a second material over the first plurality of ridges, wherein the second material forms a second plurality of ridges for the surface relief grating, wherein the second plurality of ridges is formed between the first plurality of ridges, wherein the first plurality of ridges alternates with the second plurality of ridges, and wherein the second material has a higher index of refraction than the first material.