吸収分光法の基礎

Absorption spectroscopy uses the absorption phenomena to measure concentration and temperature. The strength of the permeated light is related to the absorber concentration according to Lambert-Beer’s law. Atomic or molecular concentration and temperature are determined by the line shape functions and the Boltzmann equation. There are several methods which uses the principle of absorption phenomena. These include Tunable Diode Laser Absorption Spectroscopy (TDLAS), Fourier transform infrared spectroscopy (FTIR), non-dispersive infrared spectroscopy (NDIR), photoacoustic spectroscopy (PAS), and cavity ring-down spectroscopy (CRDS). This paper explains the basics of absorption spectroscopy for the combustion application. The basics and application of TDLAS using Computer Tomography (CT) is also introduced as a 2D measurement method which can attain the time-series imaging in measured fields.