We demonstrate a structure for a vertical-cavity surfaceemitting laser (VCSEL) with a mode filter and half-wavelength (λ/2) cavity. The effects of λ/2- and λ-cavities on the threshold current are studied. The thickness and etched diameter of the mode filter are optimised to achieve single-transverse-mode output. The results show that when changing from λ-cavity to λ/2-cavity, the threshold current of the VCSEL decreases by 30.7% (from 0.85 mA to 0.65 mA). In addition, for the mode-filter thickness of 80 nm, and the etched diameter of 2.5 μm, the side mode suppression ratio reaches 90 dB, which meets the requirement of single-transversemode output. The VCSELs with the optimised design can overcome many difficulties and have great potential in 3D face recognition.

中文翻译：

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具有模式滤波器和半波长腔的低阈值，单横模，940 nm垂直腔面发射激光器

我们演示了具有模式滤波器和半波长（λ/ 2）腔的垂直腔表面发射激光器（VCSEL）的结构。研究了λ/ 2和λ腔对阈值电流的影响。优化了模式滤波器的厚度和蚀刻直径，以实现单横模输出。结果表明，当从λ腔变为λ/ 2腔时，VCSEL的阈值电流降低了30.7％（从0.85 mA降低至0.65 mA）。另外，对于80nm的模式滤波器，蚀刻直径为2.5μm，侧模抑制比达到90dB，满足了单横模输出的要求。具有优化设计的VCSEL可以克服许多困难，并且在3D人脸识别方面具有巨大潜力。