Abstract

Optical heterodyne spectroscopy has been performed with GaAlAs diode lasers by modulating the injection current at frequencies up to 2.6 GHz. This extremely convenient modulation scheme results in simultaneous frequency and amplitude modulation of the laser output. When the modulated laser output probes a narrow absorption line, a characteristic heterodyne beat signal occurs. We show that the observed spectra are similar to those obtained in pure frequency-modulation spectroscopy. The technique offers high sensitivity and fast detection speed and is applied to the detection of water-vapor absorption lines.

© 1983 Optical Society of America

Amplitude modulation of an injection-locked semiconductor laser for heterodyne-type optical communications

K. Kikuchi, T. Okoshi, and S. Tanikoshi
Opt. Lett. 9(3) 99-101 (1984)

High-frequency-modulation spectroscopy with a lead-salt diode laser

Manfred Gehrtz, Wilfried Lenth, Anthony T. Young, and Harold S. Johnston
Opt. Lett. 11(3) 132-134 (1986)

Two-tone optical heterodyne spectroscopy with a tunable lead-salt diode laser

David E. Cooper and J. P. Watjen
Opt. Lett. 11(10) 606-608 (1986)

Frequency-modulation–polarization spectroscopy

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Opt. Lett. 8(12) 635-637 (1983)

Comparison of approaches to modulation spectroscopy with GaAlAs semiconductor lasers: application to water vapor

Liang-guo Wang, Haris Riris, Clinton B. Carlisle, and Thomas F. Gallagher
Appl. Opt. 27(10) 2071-2077 (1988)