Transparent electrode apparatus, method, and applications

Abstract

A shaped electrode on a light transmitting substrate utilizes total internal reflection to provide improved transmission of electromagnetic radiation (‘light’) compared to standard electrode designs that involve flat electrode surfaces. Redirection of incident light by a tilted or otherwise shaped contact or material added on the contact provides otherwise reflected light to an open surface region. Optional plasmon mediated focusing of incident p-polarized light may be realized.

I claim: 
     
         1 . An optical detector, comprising:
 a substrate that is one of optically transparent and having an active layer disposed on or in the substrate, having a refractive index greater than 1;   an electrode operatively coupled to the substrate, wherein said electrode has a light-receiving surface that is characterized by a given shape and/or a given optical characteristic; and   a cover layer covering at least a portion of the top surface of the substrate including the electrode,   wherein the given shape and/or the given optical characteristic of the light-receiving surface is adapted such that light incident on the light-receiving surface will be reflected there from at an angle, θ, where θ will be sufficient for total internal reflection (TIR) of light from a top surface of the cover layer.   
     
     
         2 . The optical detector of  claim 1 , wherein the cover layer is approximately index-matched with the detector material. 
     
     
         3 . The optical detector of  claim 1 , further comprising an incident light anti-reflection coating disposed on a top surface of the cover layer. 
     
     
         4 . The optical detector of  claim 1 , further comprising an anti-reflection coating disposed on or adjacent a surface of the substrate. 
     
     
         5 . The optical detector of  claim 1 , wherein the light-receiving surface of the electrode is flat and parallel to the top surface of the substrate and is covered with a material of at least one of characterized by a gradient index of refraction and a varying physical thickness to achieve light redirection to large angles. 
     
     
         6 . The optical detector of  claim 1 , wherein the light-receiving surface of the electrode is flat and angled in at least one direction with respect to the top surface of the substrate. 
     
     
         7 . The optical detector of  claim 1 , wherein the light-receiving surface of the electrode is curved. 
     
     
         8 . The optical detector of  claim 1 , wherein the electrode comprises a plurality of periodically spaced electrodes. 
     
     
         9 . A method for improving the operation of an optical detector, comprising:
 receiving incident light with the optical detector;   providing a characteristic of the optical detector to redirect the incident light within the optical detector such that incident light is substantially totally internally reflected within a cover layer of the optical detector, whereby an increased amount of the incident light is propagated in an active region of the optical detector.