Refractive boundary elements, devices, and materials
View Patent ↗An optical device includes an interface between two or more media. The refractive indices, orientations of media, and alignment relative to a propagating wave define a refractive boundary at which reflections may be reduced or eliminated, and at which, for certain incident angles, rays may be refracted on the same side of the normal as the incident ray.
1. An optical element, comprising:
a first portion having a first principal material axis with a first permittivity ∈ 1 , and a second material axis with a second permittivity β 1 ∈ 1 ;
a second portion in intimate contact with the first portion, the second portion having a second material axis and defining a two dimensional surface of incident contact and a normal axis relative to the defined two dimensional surface, the second portion having a second principal axis, a first permittivity ∈ 2 and a second permittivity β 2 ∈ 2 ;
wherein the permittivities satisfy the relationship:
β 1 ∈ 1 2 =β 2 ∈ 2 2
and the principal axis of the materials satisfy the relationship:
β
1
cos
2
ϕ
1
+
1
β
1
sin
2
ϕ
1
=
β
2
cos
2
ϕ
2
+
1
β
2
sin
2
ϕ
2
,
where φ 1 is an angle of the first principal material axis relative to the normal and φ 2 is an angle of the second principal axis relative to the normal, and wherein one of the first or second materials is a biaxial material.
2. The optical element of claim 1 wherein the defined surface is planar.
3. The optical element of claim 1 wherein β 1 is substantially 1.
4. The optical element of claim 1 wherein β 2 is substantially 1.
5. The optical element of claim 1 wherein the first portion comprises an anisotropic crystal.
6. The optical element of claim 5 wherein the second portion comprises an anisotropic crystal.