Superlens and method for making the same

Abstract

An apparatus for passive alignment of optical devices comprises a substrate including a trench in a top surface thereof, where the trench has a first end positioned at an edge of the substrate and a second end positioned at an interior region of the substrate, and a lens disposed on the top surface of the substrate adjacent to the second end of the trench. The apparatus further includes a top holder having a longitudinal indentation in a bottom surface thereof for mounting an optical fiber. The longitudinal indentation is sized to fit a top portion of the optical fiber such that a bottom portion of the optical fiber extends below the bottom surface of the top holder when the optical fiber is mounted therein. One or both of the substrate and the top holder include one or more spacer features configured for three-dimensional (3D) alignment of the lens with the optical fiber when the top holder is brought into contact with the substrate.

1 - 20 . (canceled) 
     
     
         21 . A method of making a superlens, the superlens capable of controlling the size and the phase of an electromagnetic beam, the superlens capable of independently controlling the vertical and horizontal focus of the electromagnetic beam, the method comprising:
 a. depositing a Graded Refractive Index film on a solid substrate; and   b. forming curved input and output sidewalls by photolithography and etching, the curved input sidewall being the sidewall on which the electromagnetic beam is incident, the curved output sidewall being the sidewall through which the electromagnetic beam leaves the superlens.   
     
     
         22 . The method as recited in  claim 21  wherein forming the curved input and output sidewalls comprises:
 a. depositing a metal or polysilicon layer on top of the Graded Refractive Index film; 
 b. spin-coating a photoresist layer on the metal or polysilicon layer; 
 c. writing a horizontal curved surface pattern on a standard photomask; 
 d. transferring the horizontal curved surface pattern to the photoresist layer using UV exposure with a standard mask aligner; 
 e. using dry etching to transfer the horizontal curved surface pattern from the photoresist layer to the metal or polysilicon layer; and 
 f. dry etching the Graded Refractive Index film to create a desired curved surface structure using the metal or polysilicon layer pattern as a dry etch mask. 
 
     
     
         23 . The method as recited in  claim 22  further comprising varying plasma processing parameters during dry etching to create the desired curved surface structure. 
     
     
         24 . The method as recited in  claim 22  wherein the dry etching is used in combination with a wet etching process in order to give a vertical curvature to the input and output sidewalls. 
     
     
         25 . The method as recited in  claim 21  wherein the solid substrate comprises a material selected from the group consisting of: Si, GaAs, AlN, LiNbO 3  and quartz. 
     
     
         26 . The method as recited in  claim 21  wherein the solid substrate comprises glass. 
     
     
         27 . The method as recited in  claim 21  further comprising directly fabricating the superlens on a Si or a GaAs or an InP substrate together with photonic and electronic integrated circuits as well as fiber positioning grooves. 
     
     
         28 . The method as recited in  claim 27  wherein directly fabricating the superlens comprises using photolithography to define a connection between the superlens and a waveguide. 
     
     
         29 . The method as recited in  claim 21  further comprising fabricating the superlens next to a fiber positioning V- or U-groove. 
     
     
         30 . The method as recited in  claim 21  further comprising fabricating the superlens on a substrate next to a flip-chip bonding area. 
     
     
         31 . The method as recited in  claim 21  further comprising fabricating the superlens between a fiber positioning V-groove and a flip-chip bonding area. 
     
     
         32 . A method of independently achieving desired horizontal and vertical focusing of an electromagnetic wave, the independent horizontal and vertical focusing being achieved using a superlens, the superlens comprising a vertically Graded Refractive Index multi-layer structure, the structure having one or more horizontally curved sidewalls, the method comprising:
 a. varying a thickness of the vertically Graded Refractive Index multi-layer structure to control the vertical focusing; and   b. varying a radius of curvature of the one or more horizontally curved sidewalls to control the horizontal focusing.