Optical structures including nanocrystals

Abstract

An optical structure can include a nanocrystal on a surface of an optical waveguide in a manner to couple the nanocrystal to the optical field of light propagating through the optical waveguide to generate an emission from the nanocrystal. The structure can be configured to restrict propagation of the emission from the nanocrystal along the waveguide.

1 . An optical structure comprising a layer including a nanocrystal capable of emitting light at an emission wavelength when excited by an excitation wavelength, the layer being disposed on a surface of an optical waveguide, the nanocrystal being positioned to be optically coupled to an optical field propagating through the optical waveguide, wherein the optical structure is configured to restrict propagation of the emission wavelength of light along the waveguide. 
     
     
         2 . The optical structure of  claim 1 , wherein at least one of the waveguide and the layer includes a periodic variation on a surface or interface. 
     
     
         3 . The optical structure of  claim 2 , wherein the periodic variation is configured to restrict propagation of the emission wavelength of light along the waveguide. 
     
     
         4 . The optical structure of  claim 2 , wherein the periodic variation is a periodic corrugation. 
     
     
         5 . The optical structure of  claim 1 , wherein the waveguide is an optical fiber. 
     
     
         6 . The optical structure of  claim 1 , wherein the waveguide is a planar waveguide. 
     
     
         7 . The optical structure of  claim 1 , wherein the nanocrystal is a semiconductor nanocrystal. 
     
     
         8 . The optical structure of  claim 5 , wherein the optical fiber has a cladding layer that allows light to escape at a selected amount along the length of the fiber. 
     
     
         9 . The optical structure of  claim 7 , wherein the semiconductor nanocrystal includes a core including a first semiconductor material. 
     
     
         10 . The optical structure of  claim 9 , wherein the semiconductor nanocrystal includes an overcoating on a surface of the core including a second semiconductor material. 
     
     
         11 . The optical structure of  claim 1 , further comprising a plurality of nanocrystals distributed at a first portion of the surface. 
     
     
         12 . The optical structure of  claim 11 , further comprising a plurality of nanocrystals distributed at a second portion of the surface. 
     
     
         13 . The optical structure of  claim 12 , wherein the plurality of nanocrystals distributed at the first portion of the surface has a composition different from the plurality of nanocrystals distributed at the first portion of the surface. 
     
     
         14 . A light emitting structure comprising:
 a light source arranged to introduce light including an excitation wavelength into an optical waveguide; and   a layer including a nanocrystal capable of emitting light at an emission wavelength when excited by the excitation wavelength, the layer being disposed on a surface of the optical waveguide, the nanocrystal being positioned to be optically coupled to an optical field propagating through the optical waveguide, wherein the optical structure is configured to restrict propagation of the emission wavelength of light along the waveguide.   
     
     
         15 - 26 . (canceled) 
     
     
         27 . A method of producing light comprising:
 introducing light from a light source including an excitation wavelength into an optical waveguide, the excitation wavelength propagating through the optical waveguide and optically coupling to a nanocrystal included in a layer on a surface of the optical waveguide, the nanocrystal absorbing the excitation wavelength and emitting an emission wavelength of light, wherein the optical structure is configured to restrict propagation of the emission wavelength of light along the waveguide.   
     
     
         28 - 32 . (canceled) 
     
     
         33 . The method of  claim 27 , further comprising modifying the surface of the optical waveguide to increase coupling between the optical field and the nanocrystal to allow light to escape at a selected amount at selected locations. 
     
     
         34 . The method of  claim 27 , wherein the semiconductor nanocrystal includes a core including a first semiconductor material. 
     
     
         35 . The method of  claim 27 , wherein the excitation wavelength propagates through the optical waveguide and optically couples to a plurality of nanocrystals on a first portion of a surface of the optical waveguide. 
     
     
         36 . The method of  claim 35 , wherein the excitation wavelength propagates through the optical waveguide and optically couples to a plurality of nanocrystals on a second portion of the surface. 
     
     
         37 . (canceled) 
     
     
         38 . The method of  claim 35 , wherein the plurality of nanocrystals distributed at the first portion of the surface has an emission wavelength different from the plurality of nanocrystals distributed at the first portion of the surface. 
     
     
         39 . A method of making an optical structure comprising:
 placing a layer including a nanocrystal capable of emitting light at an emission wavelength when excited by an excitation wavelength on a surface of an optical waveguide in a position to optically couple the nanocrystal to an optical field propagating through the optical waveguide; and   configuring the optical structure to restrict propagation of the emission wavelength of light along the waveguide.   
     
     
         40 . The method of  claim 39 , wherein configuring the optical structure to restrict propagation of the emission wavelength of light along the waveguide includes forming a periodic variation in at least one of the waveguide and the layer. 
     
     
         41 - 42 . (canceled) 
     
     
         43 . The method of  claim 39 , wherein placing includes dip coating, drop coating, spin coating, painting or printing the layer including the nanocrystal on the surface. 
     
     
         44 . The method of  claim 39 , further comprising processing the surface of the optical waveguide prior to placing the nanocrystal.