ABSORPTION-SPECTROSCOPY OF N2O WITH PHASE-DIFFUSION-NOISE SIDE-BAND ON A LEAD SALT TUNABLE DIODE-LASER

The broad phase-diffusion-noise spectrum of a lead-salt tunable diode laser (TDL) has been exploited for the detection of absorbances produc ed from low-pressure N2O vapor in the 4.47-mu m spectral region. This effect has previously been observed in the detection of electronic tra nsitions in rubidium, cesium, and molecular oxygen with an AlGaAs TDL operating in the 0.700-0.800-mu m region. For the first time to our kn owledge, this paper presents evidence of this phenomenon when a midinf rared rovibrational absorption line is monitored. The technique is als o compared with traditional TDL spectroscopic methods for its applicab ility to trace-vapor monitoring.