Investigation of laser‐induced grating spectroscopy of O₂ for accurate temperature measurements towards applications in harsh environments

Abstract

We present an in-depth investigation of laser-induced grating spectroscopy (LIGS) for temperature measurements in practical applications using a narrow-band dye laser with 760 nm wavelength and a pulse duration of 8 ns as the source for the pump beams creating the laser-induced grating. The pump laser wavelength was set to be either resonant with the R Q 5 ð Þ transition from the b 1 Σ + g υ 0 = 0 ð Þ X 3 Σ − g υ 00 = 0 ð Þ band of O 2 for generation of thermal LIGS or nonresonant for generation of purely electrostrictive LIGS. Signals were generated in ambient air as well as in high-pressure or high-temperature dry air mixtures. Pump laser irradiances up to 11 GW/cm 2 were used, which resulted in strong electrostrictive contribution to the overall LIGS signals at atmospheric pressure, with a low thermal contribution due to the weak absorption by the singlet O 2 b 1 Σ + g , v 0 = 0. The advantage and disadvantage of thermal or electrostrictive LIGS for temperature measurements are discussed, as well as potential applications in high-pressure environments. Furthermore, the precision of the temperature measurement is discussed by comparing different analysis methods.

ECONOS/ECW 2020: In memoriam Marcus Motzkus

“…With his frequent invited talks and contributions, he truly shaped the meetings and delivered memorable highlights. Therefore, it is no surprise that so many groups associated with ECONOS/ECW immediately committed to contribute to this special issue, [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] which happens to be the largest collection of papers in this annual series in more than a decade.…”