Publication

Sub-ppm multi gas sensing based on photoacoustic spectroscopy using DFB laser diodes

Luc Thévenaz, Stéphane Schilt, Jean-Philippe Besson
2004
Conference Papers

Abstract

Sensitive photoacoustic detection of methane (CH4), hydrogen chloride (HCI) and water vapour (H2O) in the near-infrared range using semiconductor DFB lasers is reported. A detection limit of 0.17 ppm of CH4, 0.2 ppm of HCI and 0.024 ppm of H2O (signal-to-noise ratio = 3) is reached using a properly designed photoacoustic cell operating in its first longitudinal mode.

Official source

https://infoscience.epfl.ch/entities/publication/7f54dc50-a870-4738-8f0c-3c28abe8fc21

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Luc Thévenaz, Stéphane Schilt, Jean-Philippe Besson
2004
Conference Papers

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/7f54dc50-a870-4738-8f0c-3c28abe8fc21

About this result

Related concepts (30)

Photoacoustic spectroscopy

Photoacoustic spectroscopy is the measurement of the effect of absorbed electromagnetic energy (particularly of light) on matter by means of acoustic detection. The discovery of the photoacoustic effect dates to 1880 when Alexander Graham Bell showed that thin discs emitted sound when exposed to a beam of sunlight that was rapidly interrupted with a rotating slotted disk. The absorbed energy from the light causes local heating, generating a thermal expansion which creates a pressure wave or sound.

Infrared spectroscopy

Infrared spectroscopy (IR spectroscopy or vibrational spectroscopy) is the measurement of the interaction of infrared radiation with matter by absorption, emission, or reflection. It is used to study and identify chemical substances or functional groups in solid, liquid, or gaseous forms. It can be used to characterize new materials or identify and verify known and unknown samples. The method or technique of infrared spectroscopy is conducted with an instrument called an infrared spectrometer (or spectrophotometer) which produces an infrared spectrum.

Laser diode

A laser diode (LD, also injection laser diode or ILD, or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diode's junction. Driven by voltage, the doped p–n-transition allows for recombination of an electron with a hole. Due to the drop of the electron from a higher energy level to a lower one, radiation, in the form of an emitted photon is generated. This is spontaneous emission.

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Sub-ppm multi gas sensing based on photoacoustic spectroscopy using DFB laser diodes

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