Patent ID: 6850325
Filing Date: 2005-02-01
Classification: G01P,G01S

Abstract:
1. An apparatus for the determination of a condition or state of an object based on quasi-elastic interaction between the object and light transmitted to the object, comprising: a diffractive optical element being adapted to be illuminated by a incoming light beam, the diffractive optical element comprising a diffracting region defining a diffraction plane, the incoming light beam forming an angle of incidence to a normal of the diffraction plane, the diffracting region comprising the first and second diffracting structures focussing the first and second light beams in the same focussing plane, said focussing plane being substantially perpendicular to propagation directions of the first and second light beams, the diffracting region further comprising wherein the size of the angle of incidence of the incoming light beam and the second diffraction angle are substantially equal.