报告题目：High-order harmonic generation by atoms and molecules in tailored laser fields

报告人：Prof. Wilhelm Becker, Max-Born Institute for Nonlinear Optics and Short-Pulse Spectroscopy, Germany

报告时间：7月19日下午3:00 北京时间

Zoom 会议：https://zoom.us/j/88361240855?pwd=cnJ0WUQzeFdrQ1ZJZ3VJMUIwMmFNdz09（电脑打开链接）

会议号：883 6124 0855

密码：805994

主持人：徐海峰教授

主办单位：吉林大学原子与分子物理研究所

报告摘要：

Pulses generated by the process of high-order harmonic generation (HHG) have become an indispensible tool for the investigation of the laser-matter interaction within a wide frequency regime. The standard setup is HHG by an atom in a monochromatic linearly polarized laser field, which generates linearly polarized harmonics. “Tailored” laser fields consist of superpositions of fields with different frequencies, polarizations, and crossing angles. Examples include the so-called bicircular field, i.e., two circularly polarized fields with different frequencies and opposite helicities rotating in the same plane or the OTC field, i.e. two orthogonal linearly polarized fields with different frequencies, to name the configurations that have received most attention. Tailored fields allow far-reaching control of the polarization and the spectrum (shape and cutoff) of the harmonics.

Mostly based on the strong-field approximation and the theory of quantum orbits. I shall review the various field configurations and the properties of the harmonics generated by them and try to make contact with existing experimental data. An unexpected result is that the polarization of the harmonics may depend extremely sensitively on the parameters of the driving field. For example, if the two components of the OTC field are not exactly orthogonal or not exactly linearly polarized,the harmonic polarization may dramatically change.

报告人简介：

Wilhelm Becker教授1969年毕业于德国慕尼黑工业大学，获理学博士学位，1997年至今为德国马克思-波恩研究所资深研究员、终身教授，美国物理学会以及美国光学学会Fellow，Phys. Rev. A（1999-2004）、Laser Phys. Lett.（2003至今）、ScienceOpen（2013至今）、Applied Sciences（2016至今）等期刊编委。Becker教授长期从事超快强场原子分子物理、量子光学、量子电动力学等方面的理论研究，在Science、Rev. Mod. Phys.、Phys. Rev. Lett.等SCI期刊发表论文250余篇，H指数57。