title: Ultrasensitive near-infrared cavity ring-down spectrometer for precise line profile measurement.
abstract: A cavity ring-down (CRD) spectrometer is built with a continuous-wave Ti:sapphire ring laser. Using a pair of R approximately 0.999 95 high-reflective mirrors, the noise-equivalent minimum detectable absorption loss reaches 7 x 10(-11)/cm over the spectral range of 780-830 nm. A thermal-stabilized Fabry-Perot interferometer is applied to calibrate the CRD spectrum with an accuracy of 1 x 10(-4) cm(-1). The quantitative measurement is carried out for the line profile measurements of some overtone absorption lines of C(2)H(2) near 787 nm. Doppler determined line shape has been observed with milli-Torr acetylene gas in the ring-down cavity. The instrumental line width is estimated from the line profile fitting to be <1 x 10(-4) cm(-1). It demonstrates that the CRD spectrometer with extremely high sensitivity is also very suitable for quantitative measurements including precise line profile studies in the near-infrared.
authors.affiliation: Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Gao
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.forename: An-Wen
authors.initials: AW
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Lu
authors.forename: Cun-Feng
authors.initials: CF
authors.lastname: Cheng
authors.forename: Guo-Sheng
authors.initials: GS
authors.lastname: Cheng
authors.forename: Shui-Ming
authors.initials: SM
authors.lastname: Hu