Analysis of interference in attosecond transient absorption in adiabatic condition

TL;DR

This paper simulates and analyzes interference effects in attosecond transient absorption of laser-dressed atoms, revealing how coherence phases and population dynamics influence spectral features under adiabatic conditions.

Contribution

It introduces a three-level model with adiabatic approximation to explain interference fringes and modulation signals in attosecond transient absorption spectra.

Findings

Interference fringes are linked to coherence phase differences.

Dark state sideband modulations relate to population dynamics.

Simulation results match experimental observations.

Abstract

We simulate the transient absorption of attosecond pulses of infrared-laser-dressed atoms by considering a three-level system with the adiabatic approximation. The delay-dependent interference features are investigated from the perspective of the coherent interaction processes between the attosecond pulse and the quasi-harmonics. We find that many features of the interference fringes in the absorption spectra of the attosecond pulse can be attributed to the coherence phase difference. However, the modulation signals of laser-induced sidebands of the dark state is found related to the population dynamics of the dark state by the dressing field.