title: Studies of saturated absorption and measurements of optical frequency for lines in the nu1 + nu3 and nu1 + 2nu4 bands of ammonia at 1.5 microm.
abstract: A cavity-enhanced absorption spectrometer was used to saturate several lines of ammonia in the 1510 nm - 1560 nm region. Analysis of power broadening of the saturated absorption feature for one of the ammonia lines yielded a dipole moment value comparable to that of the lines in the nu(1)+nu(3) band in acetylene. Highly reproducible frequency measurements of four ammonia line centres were carried out using a frequency comb generated by a mode-locked Cr(4+):YAG laser. These results demonstrate the possible application of ammonia saturated absorption lines for frequency metrology and calibration in a spectral region lacking strong absorbers. To our knowledge, this is the first frequency measurement of saturated absorption lines in ammonia at near infrared frequencies and the first reported observation of saturated absorption lines in the nu(1)+2nu(4) band.
authors.affiliation: Physics Department, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario, K1N 6N5, Canada. aczajkow@uottawa.ca
authors.forename: A
authors.initials: A
authors.lastname: Czajkowski
authors.forename: A J
authors.initials: AJ
authors.lastname: Alcock
authors.forename: J E
authors.initials: JE
authors.lastname: Bernard
authors.forename: A A
authors.initials: AA
authors.lastname: Madej
authors.forename: M
authors.initials: M
authors.lastname: Corrigan
authors.forename: S
authors.initials: S
authors.lastname: Chepurov
mesh_terms: D000641:Ammonia / Q000032:analysis* / Q000737:chemistry*; D007834:Lasers; D008027:Light; D012542:Scattering, Radiation; D013057:Spectrum Analysis / Q000295:instrumentation*
chemical_list: D000641:Ammonia