Spontaneous Rayleigh-Brillouin scattering spectral analysis based on the Wiener filter

Abstract

In this paper, a spontaneous Rayleigh-Brillouin scattering spectrometer is developed to measure the gaseous spontaneous Rayleigh-Brillouin scattering profiles over the pressure range from 1 to 5 atm for a wavelength of 532nm at a constant room temperature of 296K and a 90o scattering angle. In order to make a direct comparison between the experimentally obtained spectrum and the theoretical spectrum calculated from the Tenti S6 model, the measured spontaneous Rayleigh-Brillouin scattering signal is deconvolved by the Wiener filtering. The purpose is to remove the effect on the spectrum by the transmission function of the Fabry-Perrot scanning interferometer. The results of the comparison show that the deconvolved spectra are consistent with the theoretical spectra calculated from the Tenti S6 model, and thus confirm that the deconvolution based on the Wiener filter is able to process the measured spectra and improve the spectral resolution. Some factors that influence the accuracy of deconvolution are analyzed and discussed. At the same time, another comparison between the raw experimentally obtained spectra and the theoretical spectra calculated by convolving the Tenti S6 model with instrument function of the measurement system is performed in the same experimental condition. The results of the two comparisons show that, compared with the raw experimentally obtained spectrum, the deconvolved spectrum matches the theoretically calculated spectrum more accurately under lower pressure (≤2atm) than under relative higher pressure (>2atm).

Measurement of Temperature-Dependent Bulk Viscosities of Nitrogen, Oxygen and Air From Spontaneous Rayleigh-Brillouin Scattering

“…The detailed diagram of experimental device can refer to the published papers [24]- [26] and a brief introduction is made in this paper. The SRBS signals from a scattering angle at approximate 90 • , which are induced by the wavelength of 532nm with the power of 10 W under different pressures and temperatures, are recorded by the photon detector (SPCM-AQRH-14, Perkin-Elmer).…”

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

“…The RB scattering line shapes are measured by scanning the length of the scanning Fabry–Perot interferometer (FPI) with an instrument linewidth of 0.15 GHz and a free spectral range (FSR) of 10 GHz. More details of the experimental set‐up for detecting RB scattering signal have been reported in the previous study 13,14 …”

“…More details of the experimental set-up for detecting RB scattering signal have been reported in the previous study. 13,14 Part of the spontaneous RB scattering spectra with visible Mie scattering under different p-T conditions for the nitrogen are shown in Figures 1-3, with the fitting models of the S6, V3, and G3, respectively. Moreover, all of these three models are convolved with the instrument function of the FPI.…”

Measuring bulk and surface acoustic modes in diamond by angle-resolved Brillouin spectroscopy

“…Entropy fluctuation is a possible reason to cause the widening of Rayleigh line, socalled Rayleigh-center scattering [34] , but it cannot explain the phenomenon that the split-up of Rayleigh line and the blue shift of these modes. As mentioned above, the SAW peaks are broadened due to the finite numerical aperture of objective lens and…”