Eur. Phys. J. D (2016) 70: 224
https://doi.org/10.1140/epjd/e2016-70225-3

Regular Article

Effect of circularly polarized femtosecond laser pulses on alignment dynamics of linear molecules observed by strong-field photoelectron yields

¹ Department of Physics, Texas A&M University, College Station, 77843 Texas, USA
² Science Program, Texas A&M University at Qatar, 23874 Doha, Qatar
³ Department of Physics, Giresun University, 28200 Giresun, Turkey
⁴ Department of Physics, Florida Agricultural and Mechanical University, Tallahassee, 32307 Florida, USA

^a e-mail: necati@physics.tamu.edu

Received: 29 March 2016
Received in final form: 10 August 2016
Published online: 25 October 2016

Abstract

By measuring femtosecond laser driven strong-field electron yields for linear molecules aligned by circularly polarized femtosecond laser pulses, we study the rotational wavepacket evolution of N₂, CO, and C₂H₂ gas molecules. We show that circular polarization produces a net alignment along the laser pulse propagation axis at certain phases of the evolution. This gives the possibility to control alignment of linear molecules outside the plane of polarization, which can provide new capabilities for molecular imaging. The experimental results were compared to the calculated field-free molecular alignment parameter taking into account the effects of electronic structure and symmetry of the molecules. By fitting the calculated impulsive alignment parameter to the measured experimental data we determined the molecular rotational constants of the linear gas molecules.