Gasera Ltd products

Laser-based sensing techniques are attracting great interest in various fields of applications. Among various detection schemes, photoacoustic detection offers some unique features over other laser-based techniques such as low sample volume, high sensitivity and wide linear dynamic range. Signal is generated only from the absorption thus being a so called zero-background technique. The performance of a laser photoacoustic spectroscopy system depends on the availability of appropriate laser sources, modulation schemes and the pressure sensor (i.e. microphone).

Photoacoustic spectroscopy (PAS) is based on the absorption of modulated infrared light leading to the local warming of the absorbing gas volume element. The generated pressure waves are detected by a pressure detector (i.e. microphone) producing signal proportional to the absorption.

The differential photoacoustic method combines the sensitivity of photoacoustic spectroscopy with the long absorption path length used by conventional absorption spectroscopy and allows open-path and flow-through detection of gases.

FTIR is a widely used method for obtaining IR spectra of a sample. The sample is exposed to IR radiation modulated by an interferometer and the intensity of transmitted radiation is monitored via an IR detector. At certain resonant frequencies characteristic of the specific sample, the radiation will be absorbed resulting in a series of peaks in the spectrum, which can then be used to identify the sample.