Patent ID: 7196791

Claim:
A diffractive optical element device for use in spectroscopy, which comprises a light source for emitting broad-band light, a diffractive optical element towards which the light is emitted, and at least one detector for receiving the light transmitted by the diffractive optical element, characterised in that the diffractive optical element has a plurality of diffractive, dispersively focusing patterns which form one pattern plane or several non-overlapping pattern planes, wherein the respective centre of each of said pattern planes, having an optical axis at the centre, at a location where the optical axis extends through a plane of the pattern and wherein its related optical axis being two-dimensionally offset relative to each other in order to produce a plurality of spectra where at least two spectra are selected from the group consisting of: separate spectra offset relative to each other, separate spectra partly overlapping, and separate spectra offset relative to each other and partly overlapping.