A simple method is described for substantially reducing the amplitude of interference fringes that limit the sensitivities of tunable-laser high-resolution absorption spectrometers. A lead-salt diode laser operating in the 7-μm region is used with a single Brewster-plate spoiler to reduce the fringe amplitude by a factor of 30 and also to allow the detection of absorptances of 10−3% in a single laser scan without subtraction techniques, without complex frequency modulation, and without distortion of the molecular line-shape signals. Application to multipass-cell spectrometers is described.
© 1985 Optical Society of America
Original Manuscript: January 28, 1985
Manuscript Accepted: May 13, 1985
Published: September 1, 1985
Christopher R. Webster, "Brewster-plate spoiler: a novel method for reducing the amplitude of interference fringes that limit tunable-laser absorption sensitivities," J. Opt. Soc. Am. B 2, 1464-1470 (1985)