Multiphoton rovibrational excitation of diatomic molecules in the presence of an intense infrared laser beam using a non-perturbative quasi-energy technique

Abstract

A non-perturbative quasi-energy method has been developed to compute the rovibrational multiphoton excitation transition probabilities in diatomic (heteronuclear) molecules (in the electronic ground state) in the presence of an intense infrared laser beam. As the Floquet analysis is quite demanding computationally the authors therefore have resorted to a new non-perturbative quasi-energy method which not only reduces the computer time to a reasonable scale but also provides useful physical insights for the understanding of multiphoton absorption (MPA) dynamics. The practicability of this method is illustrated by computing the MPA spectra for OH, CO and HF molecules. The authors have compared their results with those obtained by exact Floquet and non-adiabatic Floquet analysis. A number of interesting features such as line broadening, dynamic Stark shift, hole-burning, etc., have been studied as a function of laser frequency and intensity.

Rashba spin–orbit interaction effect on multiphoton optical transitions in a quantum dot

“…Floquet theory relates the solution of the Schrodinger equation involving a periodic Hamiltonian to the solution of another equation with a time‐independent Hamiltonian represented by an infinite matrix called the Floquet matrix. This method, which has been applied previously to various atomic systems and nanostructures , has the distinct advantage of handling both discrete and continuous states in a single system. This paper is organized in the following way.…”

Multiphoton excitation of disc shaped quantum dot in presence of laser (THz) and magnetic field for bioimaging

“…Floquet theory relates the solution of Schrodinger equation involving a periodic Hamiltonian to the solution of another equation with a time independent Hamiltonian represented by an infinite matrix (called the Floquet matrix). Our method, which has previously applied to various atomic systems 23–25, has the distinct advantage of handling both discrete and continuum states in a single treatment. Here we use this method to explore interesting cases near resonance frequencies, that is, when detunings are small.…”

Rovibrational excitation of a diatomic molecule due to ion impact in the presence of IR laser beam

“…But when laser photon energy is quite close to the transition frequency between the initial and final states of the collision process, the effect of laser field on atomic or molecular systems can no longer be described conveniently in the framework of perturbation theory. In this regard quasi energy formalism [7][8][9][10], which makes use of the periodicity of applied field in time and a generalization of the stationary states is the most convenient and suitable. Here we use non-perturbative quasi energy method [7][8][9][10], to describe laser molecule interaction.…”

“…In this regard quasi energy formalism [7][8][9][10], which makes use of the periodicity of applied field in time and a generalization of the stationary states is the most convenient and suitable. Here we use non-perturbative quasi energy method [7][8][9][10], to describe laser molecule interaction. At present to our knowledge, there is no experimental or theoretical work available to compare with the present study.…”