Abstract
Three types of lasers have been characterized using Fourier transform emission spectroscopy and compared. The photoacoustic technique was employed to determine the detection limit of formaldehyde (less than 1 ppmV) for the strongest absorption line of the nu3 + nu5 band in the emission region of the GaInAsSb/AlGaAsSb diode laser.
The detection limit of formaldehyde was achieved. Laser sensitive detection laser absorption together with high resolution Fourier transform infrared technique including direct laser linewidth measurement, infrared photoacoustic detection of neutral molecules is discussed.
Additionally, very sensitive laser absorption techniques of such velocity modulation are discussed for case of laser application in laboratory research of molecular ions. Such sensitive techniques contributed very much in identifying laboratory microwave spectra of a series of anions.