采用Al$_{0.2}$Ga$_{0.8}$As/Al$_{0.9}$Ga$_{0.1}$As分布布拉格反射镜的光泵浦微柱激光器的低阈值激射
Low-threshold lasing of optically pumped micropillar lasers with Al$_{0.2}$Ga$_{0.8}$As/Al$_{0.9}$Ga$_{0.1}$As distributed Bragg reflectors
AI总结：
本文设计并制备含20% Al的低吸收DBRs光泵浦量子点微柱激光器，利用700–820 nm透明泵浦窗口将阈值从363.5 μW降至12.8 μW。
摘要：
我们报道了采用低吸收Al$_{0.2}$Ga$_{0.8}$As/Al$_{0.9}$Ga$_{0.1}$As介质布拉格反射镜（DBRs）而非常用GaAs/AlGaAs DBRs的光泵浦微柱激光器的设计、实现与表征。一层（In，Ga）As量子点（QDs）被嵌入GaAs $λ$腔中作为有源介质。我们通过低温光致发光实验研究所制备微柱的激射特性，泵浦激光波长在532 nm至899 nm之间变化。DBRs中20% Al含量的引入打开了700 nm至820 nm的光泵浦窗口，在该窗口内激发激光可在其带隙以上有效到达GaAs腔，同时对DBRs保持透明。这带来了显著提升的泵浦效率、低激射阈值和高热稳定性。工程化光谱窗口之外的泵浦激光波长会分别因顶部DBR的强吸收或泵浦能级激子的低效激发而导致低泵浦效率。只需将泵浦激光波长从671 nm切换到708 nm（跨越DBRs吸收边），即可证明无吸收改进型DBRs的优越性，此时激射阈值大幅降低一个数量级以上，从（363.5 ± 18.5）$μ$W降至（12.8 ± 0.3）$μ$W。
英文摘要：
We report on the design, realization and characterization of optically pumped micropillar lasers with low-absorbing Al$_{0.2}$Ga$_{0.8}$As/Al$_{0.9}$Ga$_{0.1}$As dielectric Bragg reflectors (DBRs) instead of commonly used GaAs/AlGaAs DBRs. A layer of (In, Ga)As quantum dots (QDs) is embedded in the GaAs $λ$-cavity of as an active medium. We experimentally study the lasing characteristics of the fabricated micropillars by means of low-temperature photoluminescence with varying pump laser's wavelength between 532 nm and 899 nm. The incorporation of 20% Al content in the DBRs opens an optical pumping window from 700 nm to 820 nm, where the excitation laser light can effectively reach the GaAs cavity above its bandgap, while remaining transparent to the DBRs. This results in a substantially improved pump efficiency, a low lasing threshold, and a high thermal stability. Pump laser wavelengths outside of the engineered spectral window lead to low pump efficiency due to strong absorption by the top DBR, or inefficient excitation of pump-level excitons, respectively. The superiority of the absorption-free modified DBRs is demonstrated by simply switching the pump laser wavelength from 671 nm to 708 nm, which crosses the DBRs absorption edge and drastically reduces the lasing threshold by more than an order of magnitude from (363.5 $\pm$ 18.5) $μ$W to (12.8 $\pm$ 0.3) $μ$W.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
