High signal-to-noise ratio laser technique for accurate measurements of spectral line parameters

Published

February 9, 2012

Author(s)

A. Cygan, D Lisak, S. Wojtewicz, J. Domyslawska, Joseph T. Hodges, R.S. Trawinski, R. Ciurylo

Abstract

We present a new cavity-enhanced technique for the precise measurement of absorption line shape and line position. This approach, which combines high-bandwidth locking of a continuous wave probe laser with frequency-stabilized cavity ring-down spectroscopy, enables long-term signal averaging and yields high-resolution spectra with a relatively wide dynamic range and low detection limit. By probing rovibronic transitions of the oxygen B-band near a wavelength of 689 nm, we demonstrate exceptionally precise measurements of absorption line shape and line position. We report a signal-to-noise ratio of 220,000:1 a minimum detectable absorption coefficient of 2.4E-11/cm and line center measurement with a precision of 26 kHz. In our measurements of self-broadened oxygen spectra, careful line shape analysis revealed a subtle line shape asymmetry caused by the speed dependence of the collisional shift. The precision achieved enabled us to quantify systematic line shape deviations that were approximately 1 part in 80,000 of the peak absorption. We also discuss how this method can enable experiments that address a number of fundamental physical problems including the accurate measurement of the Boltzmann constant and tests of the symmetrization postulate.

Citation

Physical Review Letters

Pub Type

Journals

Download Paper

https://doi.org/10.1103/PhysRevA.85.022508

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Keywords

oxygen, line shape, speed dependence, collisional narrowing, cavity ring-down, Boltzmann constant

Citation

Cygan, A. , Lisak, D. , Wojtewicz, S. , Domyslawska, J. , Hodges, J. , Trawinski, R. and Ciurylo, R. (2012), High signal-to-noise ratio laser technique for accurate measurements of spectral line parameters, Physical Review Letters, [online], https://doi.org/10.1103/PhysRevA.85.022508, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=909706 (Accessed October 15, 2024)