Polarization-stable single-mode 795 nm grating-coupled surface-emitting laser for quantum sensing

We demonstrate a polarization-stable and single-mode grating-coupled surface -emitting laser (GCSEL) with high side-mode suppression ratio (SMSR) of -40 dB and orthogonal polarization suppression ratio (OPSR) of -25 dB around 795 nm. The fabricated devices have low threshold current of -4.8 mA and low electrical resistance of 53 ohm at 25 degrees C. Meanwhile, a low thermal resistance of -1 K/mW is achieved, which is comparable with that of the record of ever reported for vertical-cavity surface-emitting lasers (VCSELs). The far-field divergence angle of surface-emitting beam is -14.5 degrees x14.7 degrees at an injection current of 12 mA indicating a relatively good beam quality. Our results open what we believe is a new way to produce polarization-stable single-mode surface-emitting lasers with simple fabrication process. While the GCSEL is specifically designed for quantum sensing applications such as atomic clocks, magnetometers, and gyroscope, its performance in terms of low-power consumption, low thermal resistance, good beam qualities, and wafer-level testing are of particular interest for a wide range of applications.