The Application of DFWM to the Gas Flow Measurement. Dependencies of DFWM Spectrum on Pump Intensity, Pressure, and Temperature.

Abstract

For an application of DFWM to temperature measurement of gaseous flows, we detect the DFWM spectra of iodine vapor seeded in argon and investigate fundamental properties of the spectra. The DFWM signal can be detected with the high S/N by the use of different polarizations for the input laser beams. The DFWM spectra shapes depend on the input laser intensity and pressure, mainly due to the change of ratios of the input laser intensity to the saturation intensity. The spectra also depend on temperature, because the population of iodine vapor varies wth temperature, showing the feasibility of the temperature measurement of the gaseous flows.