Abstract

A mid-infrared spectrometer with a tuning range of $>400{\mathrm{cm}}^{-1}$ in the C–H stretching region of the spectrum has been designed and constructed. The spectrometer is based on the difference-frequency generation of two tunable diode lasers in periodically poled lithium niobate waveguides. Tuning is achieved by varying a single parameter, the wavelength of one of the near-infrared input lasers. The instrument can be tuned over the entire tuning range in less than 1 s. By taking advantage of the wide tuning range, the instrument has been used to analyze a mixture of methane, ethylene, and propylene. Each of these major components was measured with an accuracy of better than 2% (where the error is defined as a percentage of the measured value) in a single 30 s long scan. When optimized, the spectrometer has the potential to meet both the performance requirements and the practical requirements for real-time process control in petrochemical manufacturing. The general principles for the design of mid-infrared spectrometers with wide tuning ranges are explained, including the use of variable waveguide fabrication recipes to create broad phase-matching resonances (which lead to broad tuning) in the desired location.

© 2007 Optical Society of America

On-line multicomponent trace-gas analysis with a broadly tunable pulsed difference-frequency laser spectrometer

Michael Seiter and Markus W. Sigrist
Appl. Opt. 38(21) 4691-4698 (1999)

Tunable dual-comb spectrometer for mid-infrared trace gas analysis from 3 to 4.7 µm

Leonard Nitzsche, Jens Goldschmidt, Jens Kiessling, Sebastian Wolf, Frank Kühnemann, and Jürgen Wöllenstein
Opt. Express 29(16) 25449-25461 (2021)

Spectroscopic detection of methane by use of guided-wave diode-pumped difference-frequency generation

Konstantin P. Petrov, Andrew T. Ryan, Thomas L. Patterson, Lee Huang, Simon J. Field, and Douglas J. Bamford
Opt. Lett. 23(13) 1052-1054 (1998)

Room-temperature mid-infrared laser sensor for trace gas detection

Thomas Töpfer, Konstantin P. Petrov, Yasuharu Mine, Dieter Jundt, Robert F. Curl, and Frank K. Tittel
Appl. Opt. 36(30) 8042-8049 (1997)

Widely tunable continuous-wave mid-infrared laser source based on difference-frequency generation in AgGaS₂

Valentin Petrov, Christian Rempel, Klaus-Peter Stolberg, and Wolfgang Schade
Appl. Opt. 37(21) 4925-4928 (1998)