Output mirror for three-colour lasers, having adjustable reflection

摘要

An output mirror for three-colour lasers, layer stacks for the blue and red component of the spectrum, optical wedge effect of at least one layer for adjusting the transmissibility in the green band. Output mirror for three-colour lasers having adjustable reflection. The invention can be used especially in ion-gas lasers which simultaneously emit three different wavelengths in the visible spectrum. In order to achieve this object, a mirror is used which consists of two layer stacks arranged one above the other, each of which consists of dielectric layers which alternately have high and low refractive indeces and have the same optical thickness. The optical thickness of an individual layer in a stack is a quarter of one wavelength in the blue part of the spectrum, and in the other stack it is a quarter of one wavelength in the red part. One of the central layers of one or both stacks has an optical layer thickness change (wedge effect). In consequence, it is possible to adjust the transmissibility in the central part of the spectrum.