Luis C. Malacarne, Nelson G. Castelli Astrath, Antonio Medina Neto, Leandro S. Herculano, Mauro L. Baesso, Paulo R. Borba Pedreira, Jun Shen, Q. Wen, Kirk H. Michaelian e Craig Fairbridge

Optics Express – Volumu: 19; Issue: 5; Pages: 4047-4058; DOI: 10.1364/OE.19.004047; 2011

We report a theoretical model and experimental results for laser-induced local heating in liquids, and propose a method to detect and quantify the contributions of photochemical and Soret effects in several different situations. The time-dependent thermal and mass diffusion equations in the presence and absence of laser excitation are solved. The two effects can produce similar transients for the laser-on refractive index gradient, but very different laser-off behavior. The Soret effect, also called thermal diffusion, and photochemical reaction contributions in photochemically reacting aqueous Cr(VI)-diphenylcarbazide, Eosin Y, and Eosin Y-doped micellar solutions, are decoupled in this work. The extensive use of lasers in various optical techniques suggests that the results may have significance extending from physical-chemical to biological applications.

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