Terahertz injection lasers based on a PbSnSe solid solution with an emission wavelength up to 50 $\mu$m and their application in the magnetospectroscopy of semiconductors

On the basis of a Pb$_{1-x}$Sn$_{x}$Se solid solution, long-wavelength diffusion injection lasers with laser generation up to a record long wavelength of 50.4 $\mu$m are created and studied. Pb$_{1-x}$Sn$_{x}$Se single crystals are grown from the vapor phase under the conditions of free growth (unseeded vapor-growth technique). By the example of a HgCdTe narrow-gap semiconductor and a quantum-well heterostructure, the possibility of applying the developed lasers in solid-state spectroscopy is demonstrated.