Method and apparatus for efficient concentration of light from laser diode arrays

DETAILED DESCRIPTION What is claimed is: 1.
A lens system for use with a light beam having a spatial cross-sectional distribution which is extended predominantly in one direction, the system comprising: a first optical element for receiving and redirecting different portions of the light beam to different locations on an imaginary plane wherein at least two portions of said light beam are directed along two non-parallel paths so as to generate a two-dimensional pattern of light on the imaginary plane; and a second optical element located at the imaginary plane and aligned with said two-dimensional pattern of light for redirecting each portion of said two-dimensional pattern of light to a focal point.
2.
The lens system of claim 1 wherein the first optical element comprises a linear array of first lenses, each of said first lenses oriented to receive and redirect a different portion of said light beam to different locations on an imaginary plane so as to generate a two-dimensional pattern of light on the imaginary plane.
3.
The lens system of claim 2, wherein the first lenses are diffractive lenses.
4.
The lens system of claim 2, wherein the first lenses are refractive lenses.
5.
The lens system of claim 4 wherein at least some of the refractive lenses have diffractive aberration correction and/or beam tilt.
6.
The lens system of claim 2 wherein the first lenses of the linear array of first lenses abut one another and wherein each of the first lenses is sized so that it will be substantially fully illuminated by the light from at least one portion of the light beam.
7.
The lens system of claim 1 wherein the second optical element comprises a two-dimensional array of second lenses located at the imaginary plane and aligned with said two-dimensional pattern of light for redirecting and focusing said two-dimensional pattern of light to a focal point.
8.
The lens system of claim 7 wherein the focal point is at infinity.
9.
The lenses system of claim 7, wherein the two-dimensional array of second lenses is a hexagonally close packed array of lenses