Analysis and design of imaging Fabry-Perot interferometers for measurement of Rayleigh-Brillouin scattering spectra in gas flows

摘要

Laser Rayleigh-Brillouin scattering is a powerful diagnostic tool for the study of gas flow properties. It provides an effective method for non-intrusive measurement of density, temperature and velocity in the gas flow. The received scattered laser light power is proportional to the gas density, the linewidth of the Rayleigh-Brillouin scattering spectrum is related to the gas temperature, and the Doppler frequency shift of the peak of the Rayleigh-Brillouin scattering spectrum is related to the gas velocity. The Rayleigh-Brillouin scattering spectrum can be measured by a Fabry-Perot interferometer operated in the imaging mode where an intensified CCD camera is frequently used to record the interference patterns of the Fabry-Perot interferometer. The Rayleigh-Brillouin scattering spectrum is then reconstructed from the measured data deconvolved with the Fabry-Perot instrument function. In this paper, the analysis and design of an imaging Fabry-Perot interferometer for the measurement of the Rayleigh-Brillouin scattering spectrum in the gas flow is presented. Some factors that limit the performance of the imaging Fabry-Perot interferometer are analyzed and discussed.