Harmonic wavelet analysis of modulated tunable diode laser absorption spectroscopy signals

Wavelet analyses of tunable diode laser absorption spectroscopy signals were performed. The absorption spectroscopy data were obtained by repeatedly scanning the beams from a tunable diode laser operating in the near infrared across absorption lines of gaseous NH(3) contained within a windowed glass tube. The laser was modulated and wavelet analyses of the absorption data were performed. It was observed that harmonic wavelets could simultaneously extract the 1f and 2f harmonics as well as higher-order harmonics from the direct absorption data.