Circular semiconductor laser having lattices for vertical emission

The present invention relates to laser devices; more precisely, it relates to laser devices which use a laser resonator that has a planar geometry to be adapted for vertical emission, i.e. orthogonal to the plane of the same laser resonator. In particular, but not exclusively, the invention is designed to be implemented in Quantum-Cascade Laser emitters, particularly when operating in the Terahertz frequency range. It is also a feature of the present invention to provide a laser resonator that allows a whispering gallery type operation mode in which the maximum radiation is obtained in a vertical direction. Furthermore the the concept here disclosed allows laser emission in a regular profile, with low divergence and high efficiency.