Sensitivity limits of a short-external-cavity tunable diode laser absorption spectrometer

short-external-cavity (SXC) is used to obtain continuous single-mode operation over 20-50 cm^-1 with near-IR semiconductor diode lasers. When the SXC lasers are used as a source in a tunable diode laser absorption spectrometer (TDLAS), very sensitive (~3x10^-6 absorbance) trace-gas detection and spectroscopic measurements are possible.