OBSERVATION OF SATURATION SPECTRUM OF THE 2-NU(3) BAND OF METHANE

We have carried out intracavity saturated absorption spectroscopy of t he 2 nu(3) band of methane using a 1.6-mu m-grating feedback external- cavity semiconductor laser. Since the narrowest linewidth of observed saturation dips is only 0.9 MHz (half-width at half-maximum), a high p otential exists for the use of this band as a precise frequency standa rd, especially when considering that the nu(3) band of methane is curr ently a well-established frequency standard.