Long-wave infrared chemical sensing based on orientation-patterned GaAs

This study employs orientation-patterned GaAs as part of a broadly tunable, continuous-wave, difference frequency generation (DFG) source for ultra-trace gas detection applications. The DFG source forms the basis of a long-wave (8-12 /spl mu/m) infrared cavity ring-down spectrometer. The combined high sensitivity of cavity ring-down spectroscopy coupled with the broad tunability of the DFG source allows both identification and quantification of a broad range of species.