Tunable, adjustable stable laser light source with spectrally filtered output

摘要

A laser light source with a broad band amplifying, narrow band tuneable active medium is characterised by a particularly high suppression of amplified spontaneous emission and side modes, by a high optical stability and by a simple design. The laser light source essentially comprises the laser medium itself, a preferably refraction-limited optical system, an angular or linear dispersing element and a reflector. The preferably flat reflector is arranged in such a way that it forms together with the imaging system a retro-reflector that works as a cat's eye reflector. The reflector is in addition partially transparent and a preferably non-reflecting spatial filter or its image is located at least approximately in the plane of the reflector, so that only spectrally filtered emissions may pass through the spatial filter and reach the reflector, where the feedback emissions are separated from the decoupled useful emissions at a single surface. In a special embodiment of the invention, the useful emission is dispersed and filtered twice before leaving the resonator, so that a particularly high suppression of luminescence and side modes is achieved. In another special embodiment of the invention, this principle is used for a multiple laser light source whose individual light sources may be synchronically tuned by means of a single element.