Actively Tunable Polar-Dielectric Optical Devices

Abstract

Optical devices that include one or more structures fabricated from polar-dielectric materials that exhibit surface phonon polaritons (SPhPs), where the SPhPs alter the optical properties of the structure. The optical properties lent to these structures by the SPhPs are altered by introducing charge carriers directly into the structures. The carriers can be introduced into these structures, and the carrier concentration thereby controlled, through optical pumping or the application of an appropriate electrical bias.

What is claimed is: 
     
         1 . An actively tunable polar-dielectric optical device, comprising:
 a plurality of local surface phonon-polariton (LSPhP) resonators situated on a substrate and a source of heat energy configured to heat the LSPhP resonators, the LSPhP resonators being fabricated from a polar-dielectric material configured to thermally excite LSPhPs that will emit photons when the material is raised to a higher temperature than its surroundings by the source of heat energy, a value of a thermal emission spectrum of the polar-dielectric material being dependent on a concentration of charge carriers in the polar-dielectric materials; and   a controllable source of charge carriers coupled to the polar-dielectric materials;   wherein the thermal emission spectrum from at least some of the LSPhP resonators can be actively tuned by controllably injecting charge carriers from the charge carrier source directly into the at least some of the resonators.   
     
     
         2 . An actively tunable polar-dielectric optical device, comprising:
 at least one polar-dielectric structure fabricated from a polar-dielectric metamaterial configured to exhibit surface polar phonon polaritons (SPhPs) affecting at least one optical property of the device when the metamaterial is subjected to an external stimulation, a value of the at least one optical property of the structure being dependent on a concentration of charge carriers in the metamaterial; and   a source of charge carriers controllably coupled to the device;   wherein the value of the at least one optical property is actively tuned by controllably injecting charge carriers from the charge carrier source directly into the polar-dielectric device.   
     
     
         3 . The actively tunable polar-dielectric optical device according to  claim 2 , wherein the at least one optical property of the structure is an effective index of refraction of the metamaterial; and;
 wherein an output angle of an optical beam incident onto the device can be actively tuned by controlling the number of charge carriers injected into the device.   
     
     
         4 . The actively tunable polar-dielectric optical device according to  claim 2 , wherein at the at least one optical property of the structure is at least one of a corresponding ordinary and a corresponding extraordinary permittivity of an anisotropic lattice of the polar dielectric material;
 wherein a value of the at least one of the corresponding ordinary permittivity and extraordinary permittivity can be actively tuned by controlling the number of charge carriers injected into the device.   
     
     
         5 . The actively tunable polar-dielectric optical device according to  claim 2 , wherein at the at least one optical property of the structure is at least one of a corresponding ordinary and a corresponding extraordinary permittivity of an anisotropic structure of a metamaterial;
 wherein a value of the at least one of the corresponding ordinary permittivity and extraordinary permittivity can be actively tuned by controlling the number of charge carriers injected into the device.   
     
     
         6 . The actively tunable polar-dielectric optical device according to  claim 2 , wherein the at least one optical property of the structure is a birefringence of the polar dielectric material;
 wherein a value of the birefringence of the polar dielectric material can be actively tuned by controlling the number of charge carriers injected into the device.   
     
     
         7 . The actively tunable polar-dielectric optical device according to  claim 2 , wherein the at least one optical property of the structure is a birefringence of an anisotropic structure of the metamaterial;
 wherein a value of the birefringence of the anisotropic structure of the metamaterial can be actively tuned by controlling the number of charge carriers injected into the device.   
     
     
         8 . The actively tunable polar-dielectric optical device according to  claim 2 , wherein the metamaterial exhibits simultaneous positive and negative real permittivities from orthogonal crystal axes in the metamaterial; and
 wherein a value of a least one of the positive and negative real permittivities can be actively tuned by controlling the number of charge carriers injected into the device.   
     
     
         9 . The optical device according to  claim 2 , wherein the charge carrier source is a controllable optical pump beam incident on the device; and
 wherein the injection of charge carriers into the device is controlled by controlling an intensity of the pump beam.   
     
     
         10 . The optical device according to  claim 2 , wherein the device is situated on a doped substrate and the charge carrier source is a controllable electrical source connected to the substrate and the device, the electrical source being configured to cause charge carriers from the substrate to be injected into the metamaterial;
 wherein the injection of charge carriers into the metamaterial is controlled by controlling an electrical signal from the electrical source.