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 apparatus for interacting with electromagnetic energy, comprising:
three or more sections in consecutive contact across two or more respective section-section interfaces, each section having a respective electromagnetic parameter different from the electromagnetic parameter of an adjacent section with at least a pair of adjacent sections having substantially different electromagnetic parameters;
wherein the three or more sections in consecutive contact are oriented so of that each the two or more section-section interfaces consecutively transmits the electromagnetic energy with substantially zero reflection even when the electromagnetic parameters of the adjacent sections on either side of the section-section interface are substantially different.
2. The apparatus of claim 1 , wherein one or more of the sections includes a manmade material.
3. The apparatus of claim 1 , wherein the electromagnetic parameters include at least one of refractive index, permittivity, or permeability.
4. The apparatus of claim 1 , wherein the electromagnetic parameters include permittivity.
5. The apparatus of claim 4 wherein
a. a first section of the three or more sections includes a first pair of permittivities, each corresponding to the other by a ratio β 1 ; and
b. a second section of the three or more sections in contact with the first section includes a second pair of permittivities, each corresponding to the other by a ratio β 2 ;
c. wherein the first and second sections include principal axes oriented such that
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
.
6. The apparatus of claim 1 , wherein the three or more sections are oriented to transmit the electromagnetic energy through each of the two or more section-section interfaces with a power loss of energy that is ideally zero.
7. The apparatus of claim 1 , wherein the three or more sections are oriented to transmit the electromagnetic energy through the two or more section-section interfaces with a power loss of energy that is that is on the order of 10 −4 or less.
8. The apparatus of claim 1 , wherein the three or more sections are oriented to transmit the electromagnetic energy through the two or more section-section interfaces with a power loss of energy that is only due to imperfections in the sections.
9. The apparatus of claim 1 , wherein the three or more sections are oriented to transmit the electromagnetic energy through the two or more section-section interfaces with no reflection at the interfaces visible to the naked eye.
10. A method of controlling propagation of RF energy comprising:
receiving input RF energy at a selected frequency; and
substantially refracting at least a portion of the input radio frequency (RF) energy at the selected frequency with substantially zero reflection.
11. The method of claim 10 wherein refracting at least a portion of the input RF energy at the selected frequency, substantially reflection free includes:
intercepting the at least a portion of the input RF energy with a material having an anisotropic dielectric constant at the selected frequency.
12. The method of claim 11 wherein refracting at least a portion of the input RF energy at the selected frequency, substantially reflection free further includes:
intercepting the at least a portion of the input RF energy with a material having a dielectric constant at the selected frequency that is a function of the anisotropic dielectric constant at the selected frequency.
13. The method of claim 12 wherein intercepting the at least a portion of the input RF energy with a material having a dielectric constant at the selected frequency that is a function of the anisotropic Dr. constant at the selected frequency includes:
intercepting the at least a portion of the input RF energy with a material having a dielectric constant that satisfies the relationship:
β
1
ɛ
1
2
=
β
2
ɛ
2
2
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:
∈ 1 is a dielectric constant of the first material relative to its principal material axis; ∈ 2 is a dielectric constant of the second material relative to its principal material axis;
β 1 ∈ 1 is a dielectric constant of the first anisotropic material relative to a second material axis; β 2 ∈ 2 is a dielectric constant of the second material relative to a second material axis; and φ 1 is an orientation angle of the principal material axis of the first anisotropic material and φ 2 is an orientation angle of the principal material axis of the second material in a region adjoining the second surface.