Ottomaniello Andrea, Conte Gloria, Pitanti Alessandro, Vicarelli Leonardo, Profeti Alessandro, Beere Harvey E, Ritchie David A, Mattoli Virgilio, Bianco Federica, Tredicucci Alessandro
Opt Express. 2021 Oct 11;29(21):33602-33614. doi: 10.1364/OE.430742.
Quantum cascade lasers (QCLs) represent a most promising compact source at terahertz (THz) frequencies, but efficiency of their continuous wave (CW) operation still needs to be improved to achieve large-scale exploitation. Here, we demonstrate highly efficient operation of a subwavelength microcavity laser consisting of two evanescently coupled whispering gallery microdisk resonators. Exploiting a dual injection scheme for the laser cavity, single mode CW vertical emission at 3.3 THz is obtained at 10 K with 6.4 mA threshold current and 145 mW/A slope efficiency up to 320 W emitted power measured in quasi-CW mode. The tuning of the laser emission directionality is also obtained by independently varying the pumping strength between the microdisks. By connecting the resonators through a suspended gold bridge, the laser out-coupling efficiency in the vertical direction is strongly enhanced. Owing to the high brightness, low-power consumption and CW operation, the proposed microcavity laser design could allow the realization of high-performance CW THz QCLs ready for massive parallelization.
量子级联激光器（QCLs）是太赫兹（THz）频段最具潜力的紧凑型光源，但连续波（CW）工作效率仍需提高才能实现大规模应用。在此，我们展示了一种由两个消逝耦合回音壁微盘谐振器组成的亚波长微腔激光器的高效运行。通过采用双注入方案对激光腔进行注入，在10 K温度下实现了3.3 THz的单模连续波垂直发射，阈值电流为6.4 mA，斜率效率为145 mW/A，在准连续波模式下测得的发射功率高达320 W。通过独立改变微盘之间的泵浦强度，还实现了激光发射方向性的调谐。通过悬挂的金桥连接谐振器，垂直方向的激光外耦合效率得到显著提高。由于具有高亮度、低功耗和连续波工作特性，所提出的微腔激光器设计有望实现适用于大规模并行化的高性能连续波太赫兹量子级联激光器。
