A. Marcano et R. Escalona, MEASUREMENT OF THE STATIONARY THERMAL NONLINEAR REFRACTION LIGHT WAVE-FRONT DISTORTIONS BY IMAGE-PROCESSING, Review of scientific instruments, 68(4), 1997, pp. 1652-1656
The thermal stationary nonlinear refraction is determined with enhance
d sensitivity by measuring the profile distortions of a cw probe light
beam in the presence of absorption of a collinearly propagating pump
light beam. By measuring the total profile distortion of the probe bea
m for different position of the sample cell, a signal similar to the w
ell-known Z-scan signal is obtained. Using the Gaussian decomposition
method a simple formula is deduced which relates the induced thermal p
hase shift to the magnitude of the observed signal. Phase shifts as lo
w as lambda/40000 with a signal-to-noise ratio of unity becomes detect
able with this technique. (C) 1997 American Institute of Physics.