All-optical field-free three-dimensional orientation of asymmetric-top molecules

Kang Lin,Wenbin Zhang,Yehiam Prior,Fenghao Sun,Junjie Qiang,Qiying Song,Ilya Sh Averbukh,Qinying Ji,Xiaochun Gong,Junyang Ma,Heping Zeng,Jian Wu,Peifen Lu,Hanxiao Li,Ilia Tutunnikov,Hui Li

doi:10.1038/s41467-018-07567-2

Abstract

Orientation and alignment of molecules by ultrashort laser pulses is crucial for a variety of applications and has long been of interest in physics and chemistry, with the special emphasis on stereodynamics in chemical reactions and molecular orbitals imaging. As compared to the laser-induced molecular alignment, which has been extensively studied and demonstrated, achieving molecular orientation is a much more challenging task, especially in the case of asymmetric-top molecules. Here, we report the experimental demonstration of all-optical field-free three-dimensional orientation of asymmetric-top molecules by means of phase-locked cross-polarized two-color laser pulse. This approach is based on nonlinear optical mixing process caused by the off-diagonal elements of the molecular hyperpolarizability tensor. It is demonstrated on SO2 molecules and is applicable to a variety of complex nonlinear molecules.

Highlights

Orientation and alignment of molecules by ultrashort laser pulses is crucial for a variety of applications and has long been of interest in physics and chemistry, with the special emphasis on stereodynamics in chemical reactions and molecular orbitals imaging
We report the experimental demonstration of all-optical field-free orientation of asymmetric-top molecules using phaselocked Orthogonal Two-Color (OTC) laser fields, consisting of fundamental wave (FW) and its temporally overlapping second harmonic (SH)
In Supplementary Note 2, we discuss a generalization of this scheme, and show how a combination of the OTC pulse with an additional linearly polarized laser pulse induces orientation in an ensemble of molecules lacking any symmetry, for example the propylene oxide