Mid-Infrared Pumped Laser-Induced Thermal Grating Spectroscopy for Detection of Acetylene in the Visible Spectral Range.
Appl Spectrosc
; 70(6): 1034-43, 2016 06.
Article
en En
| MEDLINE
| ID: mdl-27091904
ABSTRACT
We present mid-infrared laser-induced thermal grating spectroscopy (IR-LITGS) using excitation radiation around 3 µm generated by a simple broadband optical parametric oscillator (OPO). Acetylene as a typical small hydrocarbon molecule is used as an example target species. A mid-infrared broadband OPO pumped by the fundamental output of a neodymium-doped yttrium aluminum garnet (NdYAG) laser was used to generate the pump beams, with pulse energies of 6-10 mJ depending on the wavelength. The line width of the OPO idler beam was â¼5 cm(-1), which is large enough to cover up to six adjacent acetylene lines. The probe beam was the radiation of a 532 nm cw solid state laser with 190 mW output power. Signals were generated in atmospheric pressure gas flows of N2, air, CO2 and Ar with small admixtures of C2H2 A detection limit of less than 300 ppm was found for a point measurement of C2H2 diluted in N2 As expected, the oscillation frequency of the IR-LITGS signal was found to have a large dependency on the buffer gas, which allows determination of the speed of sound. Moreover, the results reveal a very strong collisional energy exchange between C2H2 and CO2 compared to the other gases. This manifests as significant local heating. In summary, the MIR-LITGS technique enables spectroscopy of fundamental vibrational transitions in the infrared via detection in the visible spectral range.
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Banco de datos:
MEDLINE
Tipo de estudio:
Diagnostic_studies
Idioma:
En
Revista:
Appl Spectrosc
Año:
2016
Tipo del documento:
Article
País de afiliación:
Suecia