Eur. Phys. J. D (2022) 76: 41
https://doi.org/10.1140/epjd/s10053-022-00358-x

Regular Article – Molecular Physics and Chemical Physics

Phase control in photodissociation of H₂ using pairs (ω,ω) of chirped laser fields

Department of Physics, Shibpur Dinobundhoo Institution (College), 412/1 G.T. Road (South), 711 102, Shibpur, Howrah, India

^a avijit_datta@yahoo.com

Received: 8 November 2021
Accepted: 26 January 2022
Published online: 7 March 2022

Abstract

We discuss the phase control in photodissociation of H₂ from the ground level X(v = 0, j = 0) to the continua of the GK and I electronic states using pairs of phase-locked laser fields of same frequencies. At the first step, a circularly polarized and shaped laser pulse of frequency ω₁ near resonantly couples the ground level X(v = 0, j = 0) with the two closely spaced nonadiabatically coupled intermediate levels B(v = 14, j = 1) and C(v = 3, j = 1). At the second step, these two intermediate levels are coupled to the dissociative continua by a linearly polarized and shaped laser pulse of suitable frequency ω₂. The single-pulse laser field of ω₁ frequency is considered to be replaced by a pair (ω₁,ω₁) of chirped and phase-locked (ϕ₁) laser field at the first step, while for the second step, the laser pulse of ω₂ frequency is considered to be replaced by a pair (ω₂,ω₂) of chirped and phase-locked (ϕ₂) laser field. We studied the phase control of the dissociation dynamics for all possible combinations of laser fields of these two steps. Variations of the relative phase differences between the two laser fields of the phase-locked shaped laser pulse pair (ω₁,ω₁) and (ω₂,ω₂) result in the control of the photodissociation dynamics of the hydrogen molecule. We demonstrate heavily enhanced phase controllability of the dissociation dynamics due to the chirping of the laser fields. Nonadiabatic interactions between the intermediate levels and predissociating bound levels have been incorporated into our calculation.