Solvated electrons in polar liquids as epsilon-near-zero materials tunable in the terahertz frequency range

Abstract

Electrons in polar liquids give rise to a polaron resonance at a terahertz (THz) frequency ν_0 depending on electron concentration. The impact of this resonance on light propagation is studied in experiments, where a femtosecond pump pulse generates electrons via multiphoton ionization and a THz probe pulse propagated through the excited sample is detected in a phase-resolved way. We observe a behavior characteristic for epsilon-near-zero (ENZ) materials with strongly modified phase and group velocities around ν_0, and a broadening of the THz pulse envelope below ν_0. Calculations based on a local-field approach reproduce the ENZ behavior.

References in corpus (4)

• Two-Dimensional Terahertz Spectroscopy of Condensed-Phase Molecular Systems
• Field-Induced Tunneling Ionization and Terahertz-Driven Electron Dynamics in Liquid Water
• Terahertz Polaron Oscillations of Electrons Solvated in Liquid Water
• Field-Induced Electron Generation in Water: Solvation Dynamics and Many-Body Interactions