Abstract: A semiconductor device comprising, a plurality of semiconductor layers having an outer semiconductor layer, and a contact layer uniformly and entirely covering said outer semiconductive layer and having over its entire surface the same material composition and abutting over its entire surface directly against said outer semiconductive layer but having only on a partial region of its surface a conductive transition to said outer semiconductive layer. The conductive transition being obtained by alloying said partial region by means of a focused laser beam pulse heating only said partial region of the contact layer to the alloying temperature, whereby alloy constituents of the melted contact material wetting said outer semiconductive layer diffuse only in a superficial zone of said outer semiconductive layer.

Abstract: A laser for the production and radiation of monochromatic light to a first polarizer arranged in the beam path of a resonator of the laser and operative to pass one of two light beam components linearly polarized perpendicularly to one another and to deflect the other linearly polarized component out of the resonator onto a photodetector for detecting that reflected part of the radiated light. A second polarizer is arranged in the direction of radiation of the light beam, behind a decoupling mirror of the resonator, and is operative to convert linearly-polarized light into circularly-polarized light. Adjacent the second polarizer in the direction of radiation is a collimator consisting of an optical system for widening the transmission beam to a remote reflector and narrowing the reflected beam received from the remote reflector back into the second polarizer and the resonator from which it is deviated onto the photodetector.