CO and CO_2 spectroscopy using a 60 nm broadband tunable MEMS-VCSEL at ~155 μm

The spectroscopic application of a new broadband microelectromechanical-system-tunable vertical cavity surface-emitting laser with single-mode coverage of $60\mathrm{nm}$ $\left(245{\mathrm{cm}}^{-1}\right)$ in a single, continuous sweep is described. The operation of the device is illustrated with high-resolution spectra of $\mathrm{CO}$ and ${\mathrm{CO}}_2$ over $110{\mathrm{cm}}^{-1}$ $\left(27\mathrm{nm}\right)$ and $67{\mathrm{cm}}^{-1}$ $\left(17\mathrm{nm}\right)$, respectively, with the $\mathrm{CO}$ band shown for high-pressure scans between 1 and $3\mathrm{ba}\text{rs}$ (0.1–0.3 MPa). The achieved tuning range opens up new opportunities for tunable diode laser absorption spectroscopy. The spectra were compared with HITRAN-derived model calculations. The benefits of a sensor based on this laser are greater speed, laser power, and tuning range.