Application of DFWM to temperature measurement of gaseous flows (Dependencies of DFWM spectrum on pump intensity, pressure, and temperature)

For an application of DFWM to temperature measurement of gaseous flows, we detect the DFWM spectra of iodine vapor seeded in argon and investigate fun damental properties of the spectra. The DFWM signal can be detected with th e high SIN by the use of different polarizations for the input laser beams. Shapes of the DFWM spectra depend on the input laser intensity and pressur e, mainly due to the change of ratios of input laser intensity to the satur ation intensity. The spectra also depend on temperature, because the popula tion of iodine vapor varies with temperature, showing the feasibility of th e temperature measurement of the gaseous flows.