Editing Tunable diode laser absorption spectroscopy (section)

{{Short description|Technique for measuring chemical composition of a gas}}
'''Tunable diode laser absorption spectroscopy''' ('''TDLAS''', sometimes referred to as TDLS, TLS or TLAS<ref>{{Cite web|title=nanoplus{{!}} Tunable Diode Laser Absorption Spectroscopy (TDLAS)|url=https://nanoplus.com/en/technology/tdlas/|website=nanoplus.com|access-date=2020-05-17}}</ref>) is a technique for measuring the concentration of certain species such as [[methane]], [[water vapor]] and many more, in a gaseous mixture using tunable [[diode laser]]s and [[laser absorption spectrometry]]. The advantage of TDLAS over other techniques for concentration measurement is its ability to achieve very low detection limits (of the order of [[Parts per billion|ppb]]). Apart from concentration, it is also possible to determine the temperature, pressure, velocity and mass flux of the gas under observation.<ref>{{cite journal | last1=Cassidy | first1=D. T. | last2=Reid | first2=J. | title=Atmospheric pressure monitoring of trace gases using tunable diode lasers | journal=Applied Optics | publisher=The Optical Society | volume=21 | issue=7 | date=1982-04-01 | issn=0003-6935 | doi=10.1364/ao.21.001185 | pages=1185–1190| pmid=20389829 | bibcode=1982ApOpt..21.1185C }}</ref><ref>{{cite journal | last1=Werle | first1=Peter | last2=Slemr | first2=Franz | last3=Maurer | first3=Karl | last4=Kormann | first4=Robert | last5=Mücke | first5=Robert | last6=Jänker | first6=Bernd | title=Near- and mid-infrared laser-optical sensors for gas analysis | journal=Optics and Lasers in Engineering | publisher=Elsevier BV | volume=37 | issue=2–3 | year=2002 | issn=0143-8166 | doi=10.1016/s0143-8166(01)00092-6 | pages=101–114| bibcode=2002OptLE..37..101W }}</ref> TDLAS is by far the most common [[Laser absorption spectrometry|laser based absorption technique]] for quantitative assessments of species in gas phase.