Scanning optics heating effects

Thermal lensing contribution to the measured nonlinear optical properties. If the pulse duration is longer than the characteristic time of the heat diffusion in the medium, or if this time is itself longer than the delay between successive pulses, material heating may lead to an observable transient thermal lens phenomenon [120, 165, 212, 218, 219], This can show itself, in experiments, with characteristics similar to those of a pure (electronic) Kerr effect. There have been some attempts to extract the respective values of the thermal and electronic contributions to y from z-scan measurements [136, 160, 165, 166, 175, 220], However, de Nalda et al. proved later that this method was not reliable enough to get quantitative results [219],... 

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