Patent ID: 6563845
Filing Date: 2003-05-13
Classification: G02F,H01S

Abstract:
An optical modulation device for coupling an entering optical radiation field to at least one of a first and second exiting optical radiation field, comprising:a first acousto-optical modulator having an acousto-optically active medium, a first sound wave field travelling through the acousto-optically active medium in a sound propagation direction, said first acousto-optical modulator, via a first acousto-optical modulation, dividing a radiation field incident in an entry direction and coupled to the entering radiation field essentially into (i) a transmitted branch propagating in a direction of a beam axis of the incident radiation field and (ii) a diffracted branch extending with a beam axis at an angle of diffraction of the first order in relation to the beam axis of the transmitted branch, wherein an angle bisector between the beam axis of the incident radiation field and the beam axis of the diffracted branch extends approximately parallel to the first sound propagation direction of the sound wave field, an optical radiation guide system for deflecting the diffracted and transmitted branches such that with their beam axes extending approximately at an angle of diffraction of the first order relative to one another these branches interact with a travelling second sound wave field having approximately the same frequency as the first sound wave field and providing a second acousto-optical modulation, said second acousto optical modulation providing: a first further diffracted branch and a first further transmitted branch from the deflected, diffracted branch, and a second further diffracted branch and a second further transmitted branch from the deflected, transmitted branch, a direction of propagation of (i) the second sound wave field, (ii) the deflected, diffracted branch and (iii) the deflected, transmitted branch being aligned relative to each other such that: (a) the first further transmitted branch and the second further diffracted branch propagate in approximately the same direction, are at least partially superimposed and thereby have essentially the same frequency, the at least partially superimposed branches forming a first radiation field as a result of essentially constructive interference, said first radiation field being coupled to the first exiting radiation field, and (b) the second further transmitted branch and the first further diffracted branch propagate in approximately the same direction, are at least partially superimposed and thereby have essentially the same frequency, these at least partially superimposed branches forming a second radiation field as a result of essentially destructive interference, said second radiation field being coupled to the second exiting radiation field.