Patent ID: 7940829

Claim:
A laser device that comprises: a rectangular enclosure of a gain medium that has two lateral mirrors, said gain medium being periodic in a lateral direction perpendicular to the said lateral mirrors, its period being related to the properties of a preferred mode, said preferred mode being one of the plane waves that can propagate in the said rectangular enclosure, said plane waves having stationary sinusoidal wave components in the lateral direction due to reflection on said lateral mirrors, said lateral component of the said preferred mode having a lateral wavelength which is twofold the period of said periodic gain and the maxima of the said periodic gain medium being situated at the intensity maxima of the stationary sinusoidal field distribution of the lateral component of the said preferred mode a back mirror perpendicular to the lateral mirrors, which together with the lateral mirrors forms an U-shaped mirror configuration, a semitransparent, low reflectivity front boundary that connects the arm's ends of the said U-shaped mirror configuration and together with the said U-shaped mirror configuration is closing the said rectangular enclosure and optical means situated externally to said front boundary to longitudinally close a resonator together with the said back mirror such that the said preferred mode couples with the said periodic gain medium, the maxima of the said periodic gain medium being situated at the intensity maxima of the stationary sinusoidal field distribution of the lateral component of the said preferred mode such that at the said front boundary the said sinusoidal field distribution of the said preferred mode is transformed in two outputs consisting of two beams emerging from said sinusoidal field distribution, said beams being symmetrically inclined relative to the normal to the said front boundary and such that said optical means situated externally to the said front boundary transform the two beams emerging from said sinusoidal field distribution into a single beam, close to a diffraction limited beam.