Diffractive optical element and method for the design of a diffractive optical element

Abstract

A diffractive optical element (DOE) is designed to implement both a collimation function with respect to an input divergent beam and a beam shaping function with respect to an output divergent beam. The phase designs of the collimation function and the beam shaping function are independently produced in the phase domain. These phase designs are then combined using a phase angle addition of the individual functions and wrapped between 0 and 2π radians. The diffractive surface of the DOE is then defined from the wrapped phase angle addition of the individual functions.

1 . An optical system, comprising:
 a collimating and beam shaping diffractive optical element configured to modify an input divergent beam and produce an output divergent beam;   wherein the collimating and beam shaping diffractive optical element comprises a diffractive surface having a design which both collimates the input divergent beam and shapes the collimated input divergent beam into the output divergent beam to form an output field with a desired output intensity distribution.   
     
     
         2 . The optical system of  claim 1 , wherein said diffractive surface is formed by a surface relief pattern designed to implement both a collimation function and a beam shaping function. 
     
     
         3 . The optical system of  claim 2 , wherein the surface relief pattern is defined by a phase combination of a phase profile for collimation of the input divergent beam and a phase profile for shaping the output divergent beam. 
     
     
         4 . The optical system of  claim 3 , wherein the surface relief pattern is further defined by a conversion of the phase combination into a physical surface relief profile. 
     
     
         5 . The optical system of  claim 3 , wherein the phase profiles for collimation and shaping are quantized phase profiles. 
     
     
         6 . The optical system of  claim 1 , wherein said diffractive surface is formed by a gradient-index (GRIN) material designed to implement both a collimation function and a beam shaping function. 
     
     
         7 . The optical system of  claim 6 , wherein the GRIN material is defined by a phase combination of a phase profile for collimation of the first divergent beam and a phase profile for shaping the second divergent beam. 
     
     
         8 . The optical system of  claim 7 , wherein the GRIN material is further defined by a conversion of the phase combination into a GRIN structure. 
     
     
         9 . The optical system of  claim 6 , wherein the phase profiles for collimation and shaping a quantized phase profiles. 
     
     
         10 . A method, comprising:
 defining a first phase profile for collimation of an input divergent beam;   defining a second phase profile for shaping an output divergent beam;   adding the first and second phase profiles to form a combined phase profile; and   forming a diffractive surface of a diffractive optical element from the combined phase profile so that the diffractive surface of the diffractive optical element is configured to both collimate the input divergent beam and shape collimated input divergent beam into the output divergent beam to form an output field with a desired output intensity distribution.   
     
     
         11 . The method of  claim 10 , wherein said diffractive surface is formed by a surface relief pattern defined from the combined phase profile to implement both a collimation function and a beam shaping function. 
     
     
         12 . The method of  claim 11 , wherein adding comprises summing a first phase profile for the collimation function and a second phase profile for the beam shaping function. 
     
     
         13 . The method of  claim 12 , wherein the first and second phase profiles are quantized phase profiles. 
     
     
         14 . The method of  claim 10 , wherein said diffractive surface is formed by a gradient-index (GRIN) material defined from the combined phase profile to implement both a collimation function and a beam shaping function. 
     
     
         15 . The method of  claim 14 , wherein adding comprises summing a first phase profile for the collimation function and a second phase profile for the beam shaping function. 
     
     
         16 . The method of  claim 15 , wherein the first and second phase profiles are quantized phase profiles. 
     
     
         17 . A method, comprising:
 independent design of a first phase profile for a collimation function and a second phase profile for a beam shaping function;   combination of the independently designed first and second phase profiles using a phase angle addition;   wrapping of the phase angle addition between 0 and 2π radians; and   production of a physical optic using a diffractive surface defined by the wrapped phase angle addition.   
     
     
         18 . The method of  claim 17 , wherein production comprises formation of a surface relief pattern designed to implement both the collimation function and the beam shaping function. 
     
     
         19 . The method of  claim 17 , wherein production comprises formation of a gradient-index (GRIN) material designed to implement both the collimation function and the beam shaping function. 
     
     
         20 . The method of  claims 17 ,
 wherein the independent design comprises independently designing the collimating function and the beam shaping function each in a phase space;   wherein combination comprises summing in the phase space the collimating function and the beam shaping function;   wherein production comprises forming a diffractive surface from the summation in phase space that will perform both the collimating and beam shaping functions.   
     
     
         21 . The method of  claim 20 , wherein the diffractive surface comprises a surface relief pattern. 
     
     
         22 . The method of  claim 20 , wherein the diffractive surface comprises a gradient-index (GRIN) material.