Multi-polariton control in attosecond transient absorption of autoionizing states

TL;DR

This paper demonstrates how tunable attosecond transient absorption spectroscopy can control autoionization states in argon, revealing multi-polariton interactions and new quantum control pathways using optical fields.

Contribution

It introduces the observation of multi-polariton formation and avoided crossings in autoionizing states via near-resonant two-photon couplings, supported by experimental and theoretical analysis.

Findings

Multiple polaritonic branches with avoided crossings observed.

One-photon dark state couplings significantly influence interactions.

Properties of autoionizing polariton multiplets are controlled by laser parameters.

Abstract

Tunable attosecond transient absorption spectroscopy is an ideal tool for studying and manipulating autoionization dynamics in the continuum. We investigate near-resonant two-photon couplings between the bright 3s^-1 4p and dark 3s^-1 4f autoionizing states of argon that lead to Autler-Townes like interactions, forming entangled light-matter states, or polaritons. We observe that one-photon couplings with intermediate dark states play an important role in this interaction, leading to the formation of multiple polaritonic branches whose energies exhibit avoided crossings as a function of the dressing-laser frequency. Our experimental measurements and theoretical essential-state simulations show good agreement and reveal how the delay, frequency, and intensity of the dressing pulse govern the properties of autoionizing polariton multiplets. These results demonstrate new pathways for quantum control of autoionizing states with optical fields.