Stimulated emission in 24–31 μm range and «Reststrahlen» waveguide in HgCdTe structures grown on GaAs

Abstract

Long-wavelength stimulated emission (SE) is studied in optically pumped HgCdTe quantum well heterostructures with dielectric waveguides. Continuous temperature tuning of the wavelength from 27 to 18  μm is achieved in structures with optimized waveguides. Above 27  μm, SE clamps at 31  μm wavelength, where mode leaking is reduced due to the Reststrahlen effect in the GaAs substrate. The operating temperature is mainly limited by the activation of Auger recombination in quasi-equilibrium conditions, while at low temperatures, we expect that lowering initial carrier heating would enhance the gain considerably. We conclude that exploiting the Reststrahlen effect should allow one to achieve continuous wavelength tuning around 30  μm and operating wavelengths up to 40  μm with technologically attainable epistructure thickness.