Noncontact Photo-Thermal Probe-Beam Deflection Measurement of Thermal Diffusivity in an Unconfined Hot Gas.

摘要

A pulsed carbon dioxide beam is used to produce a transient thermal refractive-index-gradient in nitrogen gas doped with trace amounts of absorbing Freon 12 at temperatures from 25 C to 425 C. The diffusion of this gradient is probed by a continuous HeNe laser beam parallel but displaced from the pulsed beam. The observed deflection signal agrees well with the theory of Jacson et al. (1981), and signal.