CPC G02B 27/0172 (2013.01) [G02B 6/0016 (2013.01); G02B 6/0038 (2013.01); G02B 6/0065 (2013.01); G02B 27/4205 (2013.01); G02B 27/4272 (2013.01); G02C 7/022 (2013.01); G02B 2027/0178 (2013.01); G02B 2027/0194 (2013.01)] | 23 Claims |
1. An optical device comprising:
a stack of optical elements, the stack comprising:
a first optical element stacked with a second optical element, wherein the second optical element is configured to propagate light by total internal reflection;
an incoupling diffractive grating configured to incouple the light into the second optical element; and
an outcoupling diffractive grating optically coupled to the incoupling diffractive grating through the second optical element, the outcoupling diffractive grating configured to direct the light,
wherein the first optical element has a first refractive index,
wherein the second optical element has a second refractive index, and
wherein the first refractive index is different from the second refractive index by approximately 0.3 to 1.2.
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