The aim of the project is the development of new technology of producing single frequency quantum cascade lasers (QCLs) with high beam quality. Lasers produced by standard technology are generally lacking these features. So far single frequency operation could be obtained by complicated, multistage growth process which was expensive and prone to errors.
Novelty of the proposed approach relays on elimination of the necessity of fabrication of periodic perturbation of refractive index of the active material and subsequent overgrowth, which in our case is replaced by suitable post processing of the laser. The single mode operation of the laser is enforced by using two coupled cavities (CC).