Pulsed-source thermal lens. Part 2.—Experimental tests of the theory

Abstract

The theory of the thermal lens presented in Part 1 is tested by using the decay to calculate the thermal-conductivity coefficients of Ne, Ar, Kr and Xe (48.2, 18.48, 10.05 and 6.02 W m^–1 K^–1, respectively) in terms of one adjustable parameter, the pulsed laser beam radius, which is found to be close to the measured value for the c.w. beam. These values agree closely with the best values currently available. The treatment of the rise of the thermal-lens signal is tested by comparison of observed with a priori calculated variation of maximum probe-laser modulation as a function of added Ar pressure. The system is shown to be useful for TEM₀₀ laser beam mode diameter measurement and calculation of the temporal variation of the spatial distribution of temperature in a laser-irradiated cell.