Patent ID: 6297894
Filing Date: 2001-10-02
Classification: G02B,G03H

Abstract:
An optical system for writing a spatial modulated index pattern in a material that is at least partially light transmissive or partially absorbing, comprising:an ultrafast light source for generating a pulse of laser light;a diffractive optic element having predetermined characteristics, said element being disposed to receive the pulse of laser light;an imaging and concentrating system disposed to receive at least some divergent light beams from the diffractive optic element and for concentrating and imaging received light beams at the material, the imaging and concentrating system including:a) a curved mirror disposed to receive said at least some of the divergent light beams from the diffractive optic element and to reflect the received light beams in a substantially wavelength independent manner, andb) a concentrating/focusing element for focusing and concentrating light beams reflected from the curved mirror onto the at least partially light transmissive or partially absorbing material to effect a permanent refractive index change within the material that corresponds to the spatial modulated index pattern, said curved mirror and said concentrating/focusing element being positioned relative to each other and to said diffractive optic element so as to affect each of the light beams focused and concentrated onto the at least partially light transmissive or partially absorbing material in substantially the same way in order to preserve a stable phase relationship therebetween.