| Biography | |
|---|---|
 Prof. Zuoqiang Hao Shandong Normal University, China |
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| Title: Femtosecond filamentation of interfered vortex beams | |
| Abstract: The femtosecond filamentation in transparent media is mainly supported by the dynamic competition of two nonlinear processes, the Kerr self-focusing effect and the plasma defocusing. Filamentation plays a vital role in many applications such as remote sensing, THz generation, air laser, supercontinuum source, guiding of infrared and microwave radiation in the atmosphere, pulse compression and so on. As the incident laser power exceeds many times the critical power for self-focusing, random multiple filaments will be formed, which are induced by the initial perturbation of laser pulse. In this work, controllable annular multiple filaments are obtained in fused silica by using two collinear interfered femtosecond vortex laser beams. Both the distribution and number of filaments can be well controlled with the topological charges of input beams. Furthermore, the rotation angle of the annular filaments can be freely controlled with the phase difference of interfered beams. This work provides an effective way to generate annular filaments with stable distribution, and a flexible method to control the rotating filamentation through exterior regulation, which could facilitate fabricating curved micro-nano structures in various optical media. Keyword: femtosecond filamentation, vortex beam, interference | |
| Biography: Zuoqiang Hao is currently a professor in optics at Shandong Normal University. He obtained his Bachelor's degree in physics in 2001 from Shandong Normal University, and Ph.D degree in optics in 2007 from Institute of Physics, Chinese Academy of Sciences. He was a postdoctoral researcher supported by CNRS in Lyon 1 University from 2007 to 2008, and supported by Alexander von Humboldt Foundation in Free University of Berlin from 2008 to 2011. He worked as a professor in optics at Changchun University of Science and Technology from 2011 to 2019. His current research interests include femtosecond filamentation in optical media and corresponding applications. | |
