The theory and experiment of solute migration caused by excited state absorptions

• Published in: Chinese physics B Vol. 19; no. 1; pp. 382 - 387
• Main Author: 金肖 王玉晓 税敏 李常伟 杨俊义 张学如 杨昆 宋瑛林
• Format: Journal Article
• Language: English
• Published: IOP Publishing 2010
• Subjects: Apertures; Dimethyl sulfoxide; Dissolution; Excitation; Kinetic energy; Lasers; Mathematical analysis; Migration; Nonlinearity; Saturation; Transport; Transport theory; 二甲基亚砜; 吸收峰; 溶质分子; 溶质迁移; 激发态吸收; 非线性吸收; 饱和吸收
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/19/1/014217

Nonsymmetrical transition from reverse-saturable absorption （RSA） to saturable absorption （SA） caused by excited state absorption induced mass transport of the CuPcTs dissolved in dimethyl sulfoxide is observed in an open aperture Z-scan experiment with a 21-ps laser pulse. The nonsymmetrical transition from RSA to SA is ascribed neither to saturation of excited state absorption nor to thermal induced mass transport, the so-called Sorer effect. In our consideration, strong nonlinear absorption causes the rapid accumulation of the non-uniform kinetic energy of the solute molecules. The non-uniform kinetic field in turn causes the migration of the solute molecules. Additionally, an energy-gradient-induced mass transport theory is presented to interpret the experimental results, and the theoretical calculations are also taken to fit our experimental results.