Single-shot measurement of temperature and pressure using laser-induced thermal gratings with a long probe pulse

We report accurate and precise single-shot measurements of temperature and pressure using laser-induced thermal grating spectroscopy (LITGS). The use of a flashlamp-pumped dye laser (FLPDL) as a probe for the induced gratings is described and a fast method of data analysis using Fourier methods is reported. Thermal gratings were induced by 8 ns pump pulses from a frequency-doubled Nd:YAG laser. The signals were produced by scattering 2-μs-long pulses, of energy 200 mJ, from the FLPDL. LITGS signals were obtained from NO2/N2 mixtures at pressures in the range 1-40 bar and temperatures between ambient and 400 K. Temperature values were derived from the data with an accuracy of 0.42% and a single-shot precision of 0.16%. Pressure values were obtained with an accuracy of 5.7% and a precision of 1.4% limited by uncertainties in the gas kinetic parameters