Multifocus Structures of Ultrashort Self-Focusing Laser Beam Observed in a Three-Photon Fluorescent Medium

作者：He Guang S^*; Zhang A Ping; Zheng Qingdong; Qin Hai Yan; Prasad Paras N; He Sailing; Agren Hans

来源：IEEE Journal of Quantum Electronics, 2009, 45(7): 816-824.

DOI：10.1109/JQE.2009.2014850

• Self-focusing
• multifocus structure
• three-photon excitation

Self-focusing effect and multifocus structures of an ultrashort (similar to 160-fs) pulsed laser beam of similar to 1.3-mu m wavelength are investigated in several organic liquids. The intensity-dependent self-focusing formation and multifocus structures of the infrared (IR) laser beam were directly observed in a three-photon active fluorescent dye solution cell, in which a high contrast image of the spatial structure of the self-focusing beam can be obtained due to the cubic dependence of the fluorescence intensity on the local IR laser intensity. By combining this dye solution cell with another cell filled with various transparent organic liquids, the contributions of these tested liquids to the observed self-focusing effect are elucidated. The numerical simulations for this type of self-focusing behavior are presented, based on the assumption that the major contribution to the observed self-focusing is the nonlinear refractive-index change of the solvent due to electronic-cloud distortion. The simulation results are in fairly good agreement with the experimental results.

• 出版日期2009-7
• 单位浙江大学