A compact infrared tunable room-temperature optically-pumped semiconductor laser source using epitaxially-grown transition metal-doped II-VI materials is proposed. Chromium-doped II-VI lasers have already been demonstrated using ZnS, ZnSe, CdTe, CdMnTe, and CdSe with other semiconductor hosts under investigation. Current Cr2+ lasers are relatively simple structures, presently Cr-doped bulk crystals, that operate at room temperature and are tunable over a large wavelength range (~ 2.1mm-2.8mm) with relatively temperature-insensitive operating characteristics. To achieve better performance, we propose the use of epitaxial II-VI heterostructures that will be composed of alloys of Zn1-xMgxSe and Zn1-xCdxSe grown by MBE, rather than homostructures. The II-VI waveguide laser structure with Cr-doped active layer will be grown on a GaAs substrate. Such heterostructures will confine the radiation emitted by Cr2+ to the active region, increasing the optical confinement factor. The waveguide structure may also be used to increase the optical overlap of the pump source and the optically-active Cr2+. These heterostructures will have a greatly reduced lasing threshold and increased overall efficiency as compared to the homostructures. The epitaxial structures will be characterized via photoluminescence and electron paramagnetic resonance spectroscopy. An optically-pumped Cr-doped heterostructure laser will be demonstrated using a commercially-available semiconductor laser pump.
