Simultaneous Spectroscopy of NH$_{3}$ and CO Using a ${> 50}\hbox{ nm}$ Continuously Tunable MEMS-VCSEL

Abstract

A fiber-based remote measurement setup for tunable diode laser absorption spectroscopy, introducing an electrically pumped, micromechanical vertical-cavity surface-emitting laser with single-mode emission spectrum, narrow linewidth of 40 MHz, and broadband, continuous wavelength coverage of 51 nm around 1.55 mum is presented. The tunable laser spectrometer is employed for analysis of heterogeneous gas compositions and simultaneous detection of two species, ammonia and carbon monoxide, in a single continuous wavelength sweep. Broadband absorbance spectra are captured at elevated temperatures up to 300 degC revealing opposed temperature dependencies for selected transitions.