Patent ID: 6548225
Filing Date: 2003-04-15
Classification: G02B

Abstract:
A method for creating a grating structure in a photosensitive material, the method comprising the steps of:utilizing a single coherent beam of light and a diffractions grating or other form of beam splitting device to create two coherent working beams of light; propagating the two working beams around a plurality of reflective elements comprising an even number greater than or equal to four, each of the beams being reflected by each of the reflective elements, so that the beams interfere at an initial predetermined position; positioning the photosensitive material at a second predetermined position; and rotating one or more of the reflective elements so as to independently control the period of the interference pattern and position of the interference pattern in accordance with predetermined requirements and so as to produce the grating structure in the photosensitive material; wherein when more than one of said reflective elements are rotated, all of said reflective elements being rotated are rotated simultaneously, whereby said period of said interference pattern or said position of said interference pattern, or both said period and said position of said interference pattern, can be controlled.