Spectroscopy of methane using a Nd:YAG laser at 1.34 μm

We present measurements of the absorption coefficient of methane in the v sub(2) +2v sub(3) band obtained with a neodymium:yttrium aluminum garnet (Nd:YAG) laser tuned by the use of an intracavity etalon to 7472 cm super(-) super(1) (1.3383 mu m). The linewidth of the laser was shown to be comparable to that of the pressure-broadened methane feature while the absorption coefficient of methane at 1-atm pressure was measured to be 0.59 m super(-) super(1) atm super(-) super(1) . These basic findings indicate that a practical methane detection system using laser radar (lidar) based on a Nd:YAG laser may be possible.