Patent ID: 6437886
Filing Date: 2002-08-20
Classification: G02B

Abstract:
A device for recording an interference pattern in a photosensitive medium, comprising:a laser adapted to generate a primary light beam along a path; expanding means disposed in the path of the primary light beam for spatially expanding said primary light beam, to produce an expanded light beam; and a source opaque screen provided with two openings therein, the two openings being disposed in the path of the expanded light beam, in operation light from the expanded light beam going through the two openings to produce two light beams along different paths; diffraction gratings respectively disposed in the paths of the two light beams to diffract each of said light beams into a recording beam and a corresponding monitoring beam along different paths, each recording and monitoring beams having a given intensity, the intensity of each recording beam being related to the intensity of the corresponding monitoring beam, the recording beams being incident on a recording location on the photosensitive medium and interfering at said recording location to produce the interference pattern recorded therein; and photo-detectors respectively disposed in the paths of the monitoring beams to detect the intensity thereof and allowing a monitoring of the intensity of the corresponding recording beam.