Simultaneous measurement of gas temperature and pressure based on Rayleigh–Brillouin​ scattering in kinetic region of less than one standard atmospheric pressure

In order to detect high-precision atmospheric temperature data and realize simultaneous detection of atmospheric temperature and pressure, a decoupling method for the envelope spectrum of Rayleigh–Brillouin scattering in kinetic region of less than one atmosphere is presented. The parameters of envelope spectrum are characterized by using an experimental setup with the frequency locking, continuous tunable cavity Fabry–Perot interferometer, temperature and pressure control technologies. The nitrogen with the purity of 99.99% and compressed air acted as the examples are putted into the gas cell. Combined with the characteristics of actually detecting atmospheric parameters, the correction method is adopted to eliminate the influence of residual Mie scattering on the envelope spectrum. By choosing four discrete points on the envelope spectrum of Rayleigh–Brillouin scattering, the gas temperature and pressure can be inversed. There is a nice linearity between the measured results and theoretical values. •The decoupled method is provided in kinetic region.•The simultaneous measurement of gas temperature and pressure is realized.•The effect of pressure can be eliminated in atmospheric temperature detection.•Atmospheric pressure is detected based on Rayleigh–Brillouin scattering.•The absolute detection of atmospheric temperature can be achieved.