US 11,719,886 B1
Achromatic polarization volume grating, optical waveguide system and electronic device
Lingshan Li, San Jose, CA (US)
Assigned to Goertek Inc., Shandong (CN)
Filed by Goertek Inc., Shandong (CN)
Filed on Feb. 8, 2022, as Appl. No. 17/666,731.
Int. Cl. G02B 6/34 (2006.01); G02B 5/18 (2006.01); G02B 5/30 (2006.01)
CPC G02B 6/34 (2013.01) [G02B 5/1866 (2013.01); G02B 5/3016 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A polarization volume grating, having parameters derived by performing a multivariable optimization algorithm on a merit function:
ƒk(d1,ϕ1,d2,ϕ2, . . . ,dm,ϕm,d)=[1−n1(θ,ψ)]2  (1)
wherein the parameters include d1,ϕ1,d2,ϕ2, . . . ,dm,ϕm, where m=1,2,3, . . . , and d,
wherein m is the number of layers of the polarization volume grating, dm is a thickness of an mth layer therein, ϕm is a twist angle in the mth layer, and d is a period of the polarization volume grating,
wherein k represents a central wavelength on which the multivariable optimization algorithm is performed, θ represents a polar angle of an incident light, ψ represents an azimuth angle of the incident light, and n1(θ,ψ) represents a first-order diffraction efficiency of the polarization volume grating,
wherein mcustom character2,
wherein period, twist rates of the two layers, wavelength and thickness of the polarization volume grating are selected from the following groups:
0.4 μm (100°/μm, 300°/μm), 450 nm/530 nm/630 nm, 1.8 μm;
6.5 μm, (−60°/μm, 60°/μm), 450 nm/530 nm/630 mm, 2.4 μm;
0.65 μm, (100°/μm, 300°/μm), 450 nm/530 nm /630 nm, 1.8 μm:
0.45 μm, (100°/μm, 300°/μm), 450 nm/530 nm/630 nm, 1.8 μm;
1.2 μm, (−40°/μm, 40°/μm), 450 nm/530 nm, 2.4 μm; and
1.2 μm, (−80°/μm, 80°/μm), 530 nm/630 nm, 2.4 μm.