Optical absorption spectroscopy with 1310 nm wavelength wafer-fused vertical-cavity surface-emitting lasers

1310 nm wavelength VCSELs produce single mode emission in excess of 1 mW in the temperature range of 20-70°C with a very low relative intensity noise of -148 dB/Hz. These devices have a broad tuning range of ~50 cm^-1 with variable temperature and current, which covers multiple absorption lines of methane, ammonia and hydrogen fluoride. With these VCSELs, we report optical absorption spectroscopy of several gases near 1310 nm wavelength. In particular, we report for the first time detection of HF using the absorption line in the vicinity of 7568 cm^-1 with an estimated low-pressure detection limit at the level of several ppm.