Negative refractive index materials and methods for making same

Abstract

Embodiments of the invention described herein include metamaterials that exhibit negative permittivity and negative permeability at optical frequencies, methods for preparing such materials, and devices prepared from same.

1 .- 50 . (canceled) 
     
     
         51 . A metamaterial comprising:
 a matrix material having a negative permittivity (∈) at optical frequencies; and   nanoparticles having a high dielectric constant structured to cause negative permeability (μ) at optical frequencies due to a scattering resonance.   
     
     
         52 . The metamaterial of  claim 51 , wherein the matrix material is metallic with a plasmon resonance. 
     
     
         53 . The metamaterial of  claim 51 , wherein the matrix material is one or more materials that exhibit negative permittivity and a low Drude loss factor. 
     
     
         54 . The metamaterial of  claim 51 , wherein the matrix material comprises one or more transition metals and metal alloys thereof. 
     
     
         55 . The metamaterial of  claim 51 , wherein the matrix material is polycrystalline magnesium diboride (MgB 2 ). 
     
     
         56 . The metamaterial of  claim 51 , wherein the matrix material comprises nanoparticles of material selected from gold (Au), platinum (Pt), copper (Cu), silver (Ag), nickel (Ni), palladium (Pd), cadmium (Cd), zinc (Zn), and combinations thereof. 
     
     
         57 . The metamaterial of  claim 56 , wherein the matrix material further comprises one or more polymeric materials. 
     
     
         58 . The metamaterial of  claim 51 , wherein the nanoparticles comprise one or more transition metal oxides. 
     
     
         59 . The metamaterial of  claim 51 , wherein the nanoparticles are selected from silicon carbide (SiC) nanoparticles, titanium oxide (TiO 2 ), zirconium oxide (ZrO 2 ), and combinations thereof. 
     
     
         60 . The metamaterial of  claim 51 , wherein the nanoparticles have a particle size of from about 10 nm to about 1000 nm. 
     
     
         61 . The metamaterial of  claim 51 , wherein the nanoparticles have a spherical, pyramidal, cylindrical, or tetrahedral shape. 
     
     
         62 . The metamaterial of  claim 51 , wherein the nanoparticles are in a regular arrangement. 
     
     
         63 . The metamaterial of  claim 51 , wherein the nanoparticles are in a random arrangement. 
     
     
         64 . The metamaterial of  claim 51 , wherein the nanoparticles are arranged in a gradient. 
     
     
         65 . The metamaterial of  claim 64 , wherein the nanoparticles comprise spherical nanoparticles of various sizes. 
     
     
         66 . The metamaterial of  claim 64 , wherein the gradient provides a negative gradient index of refraction. 
     
     
         67 . The metamaterial of  claim 51 , wherein the nanoparticles are from about 10% by volume to about 50% by volume of the metamaterial. 
     
     
         68 . The metamaterial of  claim 51 , further comprising a surfactant, binder, or combination thereof. 
     
     
         69 . The metamaterial of  claim 68 , wherein the surfactant, binder, or combination thereof comprises less than about 25% by volume of the metamaterial. 
     
     
         70 . The metamaterial of  claim 51 , wherein the metamaterial is a film having a thickness of from less than about 10 μm to about 25 mm. 
     
     
         71 . The metamaterial of  claim 51 , wherein the metamaterial is a coating having a thickness less than about 10 μm. 
     
     
         72 . The metamaterial of  claim 51 , wherein the metamaterial exhibits a negative refractive index within the visible spectrum. 
     
     
         73 . The metamaterial of  claim 51 , wherein the metamaterial exhibits one or more negative refractive index band from about 250 nm to about 1500 nm. 
     
     
         74 . The metamaterial of  claim 51 , wherein the Drude loss factor of the matrix material is less than about 0.1. 
     
     
         75 . The metamaterial of  claim 51 , wherein the material is optically isotropic. 
     
     
         76 . A lens comprising:
 a matrix material having a negative permittivity (∈) at optical frequencies; and   nanoparticles having a high dielectric constant structured to cause negative permeability (μ) at optical frequencies due to a scattering resonance.   
     
     
         77 . The lens of  claim 76 , wherein the nanoparticles are arranged in a gradient. 
     
     
         78 . The lens of  claim 76 , wherein the lens exhibits a negative index of refraction. 
     
     
         79 . A method for focusing parallel beams of light comprising directing a beam of light through a lens having a negative gradient of refraction. 
     
     
         80 . The method of  claim 79 , wherein the lens comprises:
 a matrix material having a negative permittivity (∈) at optical frequencies; and   nanoparticles having a high dielectric constant structured to cause negative permeability (μ) at optical frequencies due to a scattering resonance arranged in a gradient.   
     
     
         81 . The method of  claim 79 , wherein the beam of light emanates from an object in far field of the lens.