Spontaneous emission and lasing of a two-wavelength quantum-cascade laser

The results of experiments on the fabrication (by molecular-beam epitaxy) and investigation of the heterostructures of a two-frequency quantum-cascade laser produced on the basis of a heteropair of In$_{0.53}$Ga$_{0.47}$As/Al$_{0.48}$In$_{0.52}$As solid solutions on an InP substrate are presented. The heterostructures contained quantum cascades emitting at a wavelength of 9.6 $\mu$m and cascades emitting at a wavelength of 7.6 $\mu$m. The high structural quality of the fabricated heterostructures is shown. The spontaneous emission and lasing spectra are investigated and the multimodal laser generation of stripe lasers at a wavelength of 7.6 $\mu$m is demonstrated.