Abstract

Measurements in the infrared region using semiconductor lasers, particularly as applied to atmospheric pollution monitoring, depend critically on the availability of reliable line positions and linewidth information. We demonstrate a unique internal calibration technique such that spectral locations can be determined accurately, to the order of the monochromaticity of the laser. This is based on low-pressure absorption measurements and subsequent fitting of a Voigt profile and determining the Doppler component. With this technique, we are able to determine the self- and the N₂-broadening parameters of the NH₃ line at 852.7 cm⁻¹ to be 26.2 ± 0.4 MHz Torr⁻¹ and 5.2 ± 0.1 MHz Torr⁻¹, respectively. Also, the spectral locations for several SO₂ lines in the 1180.1 cm⁻¹ region were determined accurately.

Near-infrared diode laser spectrometer with frequency calibration using internal second harmonics

Hideto Kanamori, Shigehiro Takashima, and Katsumi Sakurai
Appl. Opt. 30(27) 3795-3798 (1991)

Absorption Line Parameter Measurements Using Laser Spectroscopy

Z. Kucerovsky, E. Brannen, D. G. Rumbold, and W. J. Sarjeant
Appl. Opt. 12(2) 226-231 (1973)

Measurement of molecular concentrations and line parameters using line-locked second harmonic spectroscopy with an AlGaAs diode laser

Neil Goldstein, Steven Adler-Golden, Jamine Lee, and Fritz Bien
Appl. Opt. 31(18) 3409-3415 (1992)

Nitric acid vapor line parameters measured by CO laser transmittance

L. A. Farrow, R. E. Richton, and C. P. Karnas
Appl. Opt. 18(1) 76-81 (1979)

Linewidth measurements of tunable diode lasers using heterodyne and etalon techniques

J. Reid, D. T. Cassidy, and R. T. Menzies
Appl. Opt. 21(21) 3961-3965 (1982)