We report on a pump–probe mode-mismatched thermal-lens Z-scan method for the measurement of small absorption coefficients. In this method the pump light beam is focused into the sample to induce a thermal lens, which is tested by a collimated probe-light beam. Comparison between mode-matched and mode-mismatched Z-scan schemes is performed by use of a Fresnel-diffraction approximation model. This method is used to measure the absorption of distilled water and optical glass in the near-infrared and visible regions of the spectrum.
© 2002 Optical Society of America
(190.4870) Nonlinear optics : Photothermal effects
(190.5940) Nonlinear optics : Self-action effects
(350.5340) Other areas of optics : Photothermal effects
(350.6830) Other areas of optics : Thermal lensing
Aristides Marcano, Curtis Loper, and Noureddine Melikechi, "Pump–probe mode-mismatched thermal-lens Z scan," J. Opt. Soc. Am. B 19, 119-124 (2002)