Methane detection with a narrow-band source at 34 μm based on a Nd:YAG pump laser and a combination of stimulated Raman scattering and difference frequency mixing

Abstract

We report the characterization of a 10-Hz pulsed, narrow-band source that is coincident with a fundamental ν(3) rovibrational absorption of methane at 3.43 µm. To generate this midinfrared wavelength, an injection-seeded 1.06-µm Nd:YAG laser is difference frequency mixed with first Stokes light generated in a high-pressure methane cell (1.06 ? 1.54 µm) to result in light at a wavelength of 3.43 µm, that is, the ν(1) Raman active frequency of methane (~2916.2 cm(-1)). With a modest-energy Nd:YAG laser (200 mJ), a few millijoules of this midinfrared energy can be generated with a pulse width of ~7 ns (FWHM). The methane ν(1) frequency can be pressure tuned over 8-32 atm (corresponding to ~13 GHz) and scanned across part of the ν(3)P(10) rovibrational level of methane, resulting in a peak measured methane absorption coefficient of 4.2 cm(-1) atm(-1).

Compact CH4 sensor system based on a continuous-wave, low power consumption, room temperature interband cascade laser

“…The ability to monitor methane (CH 4 ) in urban and rural areas is critical, 1,2 as methane is a key contributor to the greenhouse effect and a safety hazard in several industries, including natural gas storage, transportation, coal mining, and the handling of liquefied methane. Optical methods based on infrared laser spectroscopy are desirable for methane sensing, [3][4][5][6][7] because they do not require pretreatment and accumulation of the concentration of the analyzed sample, unlike, for example, more conventional methods such as mass spectrometry or gas chromatography. In addition, optical methods provide high precision remote sensing capabilities and fast response.…”

Development and field deployment of a mid-infrared methane sensor without pressure control using interband cascade laser absorption spectroscopy

“…In comparison with mass spectrometry or gas chromatography, optical methods based on infrared laser spectroscopy [13][14][15][16][17] are advantageous for CH 4 sensing in terms of size, time resolution and cost and require no pretreatment and/or accumulation of the concentration of the targeted gas samples. Tunable infrared laser absorption spectroscopy (TLAS) [18][19][20] enables non-contact measurements and has proven to be an excellent tool for trace gas detection in various applications.…”

“…sensor system without pressure control was developed using a 3.291 μm TEC,14 CW ICL and a dense patterned MPGC with an effective 54.6 m optical path length. The ICL targeted a strong CH 4 absorption line at 3038.5 cm -1 in the fundamental absorption band of CH4 .…”

A compact mid-infrared dual-gas CH4/C2H6 sensor using a single interband cascade laser and custom electronics

“…Infrared laser spectroscopy [5][6][7][8][9] is advantageous compared to other detection methods in terms of cost, size and no sample pretreatment. Furthermore, TDLAS can achieve high-precision sensing capabilities and fast response.…”