Development of Cr2+-Doped II-VI Heterostructure Laser Grown by Molecular Beam Epitaxy for Room-Temperature Infrared Applications

利用外延生长过渡金属掺杂的II-VI材料，提出了一种紧凑的室温红外可调谐光泵浦半导体激光源。掺杂铬的II-VI激光器已经被证明使用ZnS， ZnSe, CdTe， CdMnTe和CdSe与其他正在研究的半导体主体。目前的Cr2+激光器是相对简单的结构，目前是掺cr的块状晶体，在室温下工作，可在大波长范围（~ 2.1mm-2.8mm）内调谐，具有相对温度不敏感的工作特性。为了获得更好的性能，我们建议使用由MBE生长的Zn1-xMgxSe和Zn1-xCdxSe合金组成的外延II-VI异质结构，而不是同质结构。在GaAs衬底上生长了掺杂cr有源层的II-VI波导激光器结构。这种异质结构将Cr2+发射的辐射限制在有源区域，增加了光学约束因子。波导结构还可用于增加泵浦源和光学活性Cr2+的光学重叠。与同质结构相比，这些异质结构将大大降低激光阈值并提高整体效率。外延结构将通过光致发光和电子顺磁共振谱来表征。光泵浦掺铬异质结构激光器将演示使用商用半导体激光泵浦。

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.