讲座题目：Harmonic generation in aligned and spinning molecules

主讲人：Prof. Olivier FAUCHER

主持人：吴健教授

讲座时间：2017.10.29  上午10:00

讲座地点：中北校区理科大楼A814室

报告人简介：

POSITIONS HELD

1991-1994: Post doctoral fellow, Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion, Greece.

1994-1995: Associate Researcher, IESL, FORTH, Heraklion, Greece.

2005-today: Professor Physics Department, University of Bourgogne, France.

EDUCATION

1982-1986: Physics Diploma / University of Lille I / France

1986-1987: DEA « Interactions rayonnement matière » / University of Lille I / France

1987-1991: Ph. D. Physics / Centre CEA Saclay / FranceRESEARCH TOPICS

Atoms and molecules in strong and ultrafast laser fields

报告摘要：

A fascinating way to control molecular rotation is to kick molecules with an intense laser pulse of well-defined amplitude, shape, and polarization. When the duration of the pulse is short on the scale of molecular rotation, the impulse delivered to the molecule is converted into angular localization of the molecular axis periodically occurring after laser turn off. This talk presents two intriguing phenomena observed in strongly-driven molecular rotors. The first one is about the production of coherent extreme ultraviolet radiation (XUV) of controlled polarization [1]. A circularly-polarized (CP) laser pulse is used to generate highorder harmonics in a gas jet of linear molecules previously aligned by a linearly polarized short laser pulse. By acting on the temporal delay between the two pulses, a control over the polarization state of the generated XUV radiation can be applied. High-order harmonics generated with high ellipticity (close to unity) are thus demonstrated. The second one is related to the observation of the rotational Doppler effect in the nonlinear interaction of a CP laser pulse with fast spinning molecules [2]. A gas ensemble of spinning molecules prepared by a pulse exhibiting a linear twisted polarization is exposed to a CP fundamental pulse driving a third-harmonic generation process. By recording the harmonic spectra for different handednesses of the photon polarization and molecule rotation, the whole set of nonlinear rotational Doppler frequency shifts envisioned by Simon and Bloembergen almost 50 years ago [3] could be observed.