Field-free orientation of CO molecules by femtosecond two-color laser fields

TL;DR

This paper demonstrates the first experimental realization of non-adiabatic, field-free orientation of CO molecules using a two-color femtosecond laser field, enabling new studies of molecular dynamics without external fields.

Contribution

It introduces a novel method for controlling molecular orientation with two-color femtosecond lasers and compares experimental results with quantum calculations.

Findings

Successful non-adiabatic orientation of CO molecules achieved

Orientation controlled via relative phase of two-color laser field

Method applicable to various molecular spectroscopy techniques

Abstract

We report the first experimental observation of non-adiabatic field-free orientation of a heteronuclear diatomic molecule (CO) induced by an intense two-color (800 and 400 nm) femtosecond laser field. We monitor orientation by measuring fragment ion angular distributions after Coulomb explosion with an 800 nm pulse. The orientation of the molecules is controlled by the relative phase of the two-color field. The results are compared to quantum mechanical rigid rotor calculations. The demonstrated method can be applied to study molecular frame dynamics under field-free conditions in conjunction with a variety of spectroscopy methods, such as high-harmonic generation, electron diffraction and molecular frame photoemission.