Optical unit, illumination optical apparatus, exposure apparatus, and device manufacturing method

Abstract

An illumination optical apparatus has an optical unit. The optical unit has a light splitter to split an incident beam into two beams; a first spatial light modulator which can be arranged in an optical path of a first beam; a second spatial light modulator which can be arranged in an optical path of a second beam; and a light combiner which combines a beam having passed via the first spatial light modulator, with a beam having passed via the second spatial light modulator; each of the first spatial light modulator and the second spatial light modulator has a plurality of optical elements arranged two-dimensionally and controlled individually.

What is claimed is: 
     
         1 . An optical unit comprising:
 a light splitter, arranged in an incident light path, to split an incident beam traveling in the incident light path, into a plurality of beams;   a first spatial light modulator which can be arranged in an optical path of a first beam out of the plurality of beams;   a second spatial light modulator which can be arranged in an optical path of a second beam out of the plurality of beams; and   a light combiner, arranged in an exiting light path, to combine a beam having passed via the first spatial light modulator, with a beam having passed via the second spatial light modulator, and to direct a resultant beam to the exiting light path,   wherein at least one spatial light modulator out of the first spatial light modulator and the second spatial light modulator includes a plurality of optical elements arranged two-dimensionally and controlled individually, and   wherein the incident light path on the light splitter side and the exiting light path on the light combiner side extend in the same direction.