A review of developments in near infrared methane detection based on tunable diode laser

Diode laser based absorption spectroscopy (DLAS) is widely used for gas detection in variety of applications across the energy, petrochemical and mining industries. Recent developments in near and mid infrared diode lasers have improved the sensitivity of gas measurement based on high resolution spectra of target species. The availability of near-infrared diodes that can operate at room temperature has expanded the application of spectroscopy technique in hand-held gas detection devices. DLAS in conjunction with optical fibres has also been applied for the distributed sensing and monitoring of various gases in real-time basis. This paper, after introducing methane characteristics and semiconductor diode lasers, comprehensively reviews development in spectroscopic methane sensing techniques in accordance with methane absorption lines in the near infrared spectrum.