Sensitive detection of methane with a 1.65 μm diode laser by photoacoustic and absorption spectroscopy

Schäfer, Stefan; Mashni, M.; Sneider, J.; Miklós, András; Hess, Peter; Pitz, H. H.; Pleban, K.-U.; Ebert, Volker

doi:10.1007/s003400050426

Cited by 47 publications

(35 citation statements)

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“…Taking into account the low optical power injected in the PA cell (typically 0.3 mW), the obtained sensitivity is comparable to results previously reported in the 1.65 m range using standard telecommunication DFB lasers and longitudinal acoustic resonators [12][13][14], but slightly lower than values reached using differential Helmholtz resonators [15,16]. These results are however far from the best reported sensitivity (close to 1 ppb) for PA methane detection [17], achieved in the 3.3 m region, where the CH 4 absorption is more than one-order of magnitude higher than in the 1.65 or 2.37 m ranges, and with a 200 times higher optical power delivered by an optical parametric oscillator.…”

Section: Resultssupporting

confidence: 84%

Application of antimonide diode lasers in photoacoustic spectroscopy

Schilt

Vicet

Werner

et al. 2004

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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First investigations of photoacoustic (PA) spectroscopy (PAS) of methane using an antimonide semiconductor laser are reported. The laser fabrication is made in two steps. The structure is firstly grown by molecular beam epitaxy, then a metallic distributed-feedback (DFB) grating is processed. The laser operates at 2371.6 nm in continuous wave and at room temperature. It demonstrates single-mode emission with typical tuning coefficients of 0.04 nm mA −1 and 0.2 nm K −1 . PA detection of methane was performed by coupling this laser into a radial PA cell. A detection limit of 20 ppm has been achieved in a preliminary configuration that was not optimised for the laser characteristics.

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Section: Resultssupporting

confidence: 84%

Application of antimonide diode lasers in photoacoustic spectroscopy

Schilt

Vicet

Werner

et al. 2004

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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“…In such a case an open photoacoustic cell should be used. of the standing wave [11,12]. However, in the case of a Helmholtz resonator the fluid which fills the cell is pumped between the cavities synchronously with the light stimulation without producing any standing wave.…”

Section: Introductionmentioning

confidence: 99%

Differential Open Photoacoustic Helmholtz Cell

Starecki

Geras

2014

Int J Thermophys

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There are very few designs of the open photoacoustic Helmholtz cells, and most of them exhibit very strong penetration of the external acoustic noise inside the cell. So far the best values of external acoustic noise suppression obtained in such cells were reported at the level of about 40 dB to 50 dB. This paper presents an open photoacoustic Helmholtz cell design with a differential signal detection. Both Helmholtz resonator cavities are equipped with microphones and connected with the exterior via duct-buffer-duct structures. The length and diameter of the ducts as well as volume of the acoustic buffers are selected in such a way that the acoustic impedance of the duct-buffer-duct structure at the frequency of light modulation is relatively high. As a result, the resonance of the cell is not damped, while penetration of the external acoustic noise inside the cell is strongly reduced. Preliminary analysis predicts attenuation of the external acoustic noise at the resonance frequency of the cell with a single microphone to be at the level of at least 60 dB. Additional rejection of the external acoustic noise can be obtained with differential detection, which simultaneously doubles the photoacoustic signal component; as in the Helmholtz resonator, pressure changes in the cavities are in counterphase.

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“…Diode-laser photoacoustic (DL-PA) measurements of methane absorption in the near-infrared (NIR) spectral region at 1660 nm were reported in ref 11. The advantage of NIR diodes is that they work at room temperature, the disadvantage of the NIR spectral range is the low absorption coefficient of overtone and combination bands.…”

Section: Introductionmentioning

confidence: 99%

Photoacoustic Trace Detection of Methane Using Compact Solid-State Lasers

Liang¹,

Liu²,

Kung

et al. 2000

J. Phys. Chem. A

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Methane was excited in the near-infrared (NIR) region using a pulsed grazing-incidence periodically poled lithium niobate optical parametric oscillator (OPO) and modulated diode laser radiation at 1650 nm as light sources and detected photoacoustically employing single tube and double tube acoustic resonators coupled with acoustic filters. The output power of the OPO was ∼60 mW at the acoustic resonance frequency of 2.12 kHz, and therefore much higher than that of the diode laser radiation with 2 mW. By combining the more powerful OPO with the more sensitive differential cell with two resonator tubes (sensitivity: R min W ) 1.2 × 10 -9 cm -1 W), an ultimate sensitivity of 20-30 parts per billion (ppbV) is estimated for methane detection with the signal beam of the OPO in the near-infrared and sub-ppbV sensitivity in the mid-infrared region with the idler beam.

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Sensitive detection of methane with a 1.65 μm diode laser by photoacoustic and absorption spectroscopy

Cited by 47 publications

References 0 publications

Application of antimonide diode lasers in photoacoustic spectroscopy

Application of antimonide diode lasers in photoacoustic spectroscopy

Differential Open Photoacoustic Helmholtz Cell

Photoacoustic Trace Detection of Methane Using Compact Solid-State Lasers

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