Brillouin shift and temperature measurement by spontaneous Rayleigh‐Brillouin scattering profiles using different models

Abstract

AbstractSpontaneous Rayleigh‐Brillouin scattering spectra in nitrogen have been measured in the pressure range from 4 to 7 bar at a wide temperature from 291 to 399 K with a scattering angle of about 90°, and then fitted to different theoretical models (S6, V3, and G3). The result of the root‐mean‐square errors of fitting residuals shows that the V3 and G3 models have good fitting performance. However, compared to the predicted Brillouin shift, the maximum relative errors in deducing the Brillouin shift from fitted data are 0.6% for the S6, 3.3% for the V3 and 4.6% the G3 models. The S6 model is the most accurate model in retrieving temperature for the absolute error below 3.5 K while the absolute error is less than 25 K for the V3 model and 35 K for the G3 model. Although the V3 and G3 models may not be suitable for the atmospheric temperature measurement, they are more potential for the high‐temperature measurement of unknown environmental pressures.