Waveguide with birefringent organic solid crystal layer
An optical element includes a waveguide body that is configured to guide light by total internal reflection from an input end to an output end, an input coupling structure located at the input end for coupling light into the waveguide body, and an output coupling structure located at the output end for coupling light out of the waveguide body, where the waveguide body includes a layer of an organic solid crystal. Such an optical element may have low weight and exhibit good color uniformity.
1 . An optical element comprising:
a waveguide body extending from an input end to an output end and configured to guide light by total internal reflection from the input end to the output end;
an input coupling structure located at the input end for coupling light into the waveguide body;
an output coupling structure located at the output end for coupling light out of the waveguide body, wherein the waveguide body comprises a layer of an organic solid crystal;
a first orientation layer disposed between the waveguide body and the input coupling structure; and
a second orientation layer disposed between the waveguide body and the output coupling structure.
2 . The optical element of claim 1 , wherein the input coupling structure and the output coupling structure each comprise a plurality of diffractive gratings.
3 . The optical element of claim 2 , wherein the diffractive gratings are selected from the group consisting of polarization volume holographic (PVH) gratings and surface relief gratings (SRG).
4 . The optical element of claim 2 , wherein the diffractive gratings comprise binary phase gratings or slanted gratings.
5 . The optical element of claim 1 , wherein the optical element comprises a planar waveguide.
6 . The optical element of claim 1 , wherein the optical element comprises a non-planar waveguide.
7 . The optical element of claim 1 , wherein the waveguide body comprises two or more organic solid crystal layers.
8 . The optical element of claim 1 , wherein the waveguide body comprises a molecule selected from the group consisting of anthracene, tetracene, pentacene, saturated or unsaturated polycyclic hydrocarbons, nitrogen-, sulfur-, or oxygen-containing heterocycles, quinolines, benzothiophenes, benzopyrans, bent and asymmetric acenes, 2,6-naphthalene dicarboxylic acid, and 2,6-dimethyl carboxylic esters.
9 . The optical element of claim 1 , wherein the waveguide body comprises a single crystal.
10 . The optical element of claim 1 , wherein the waveguide body comprises a refractive index of at least approximately 1.5 and a birefringence of at least approximately 0.05.
11 . The optical element of claim 1 , wherein the waveguide body comprises principal refractive indices (n x , n y , n z ), wherein n x =n y =n z , n x ≠n y ≠n z , n x =n y ≠n z , n x =n z ≠n y , Or n y =n z ≠n x .
12 . The optical element of claim 1 , wherein the first and second orientation layers each have a refractive index along at least one principal axis greater than the extraordinary refractive index of the waveguide body.
13 . The optical element of claim 1 , wherein a thickness of each of the first and second orientation layers is less than approximately 100 nm.