Amplification of intense light fields by nearly free electrons

Abstract

Light can be used to modify and control properties of media, as in the case of electromagnetically induced transparency or, more recently, for the generation of slow light or bright coherent XUV and X-ray radiation. Particularly unusual states of matter can be created by light fields with strengths comparable to the Coulomb field that binds valence electrons in atoms, leading to nearly-free electrons oscillating in the laser field and yet still loosely bound to the core [1,2]. These are known as Kramers-Henneberger states [3], a specific example of laser-dressed states [2]. Here, we demonstrate that these states arise not only in isolated atoms [4,5], but also in rare gases, at and above atmospheric pressure, where they can act as a gain medium during laser filamentation. Using shaped laser pulses, gain in these states is achieved within just a few cycles of the guided field. The corresponding lasing emission is a signature of population inversion in these states and of their stability against ionization. Our work demonstrates that these unusual states of neutral atoms can be exploited to create a general ultrafast gain mechanism during laser filamentation.

arXiv comment9 pages, 4 figures, 10 pages supplementary material, 8 supplementary figures

References in corpus (9)

• Lorentz meets Fano spectral line shapes: A universal phase and its laser control
• High gain backward lasing in air
• High-brightness switchable multi-wavelength remote laser in air
• Population Redistribution among Multiple Electronic States of Molecular Nitrogen Ions in Strong Laser Fields
• Recollision induced superradiance of ionized nitrogen molecules
• Self-seeded lasing in ionized air pumped by 800 nm femtosecond laser pulses
• Lasing of ambient air with microjoule pulse energy pumped by a multi terawatt IR femtosecond laser
• XUV lasing during strong-field assisted transient absorption in molecules
• Non-linear Synthesis of Complex Laser Waveforms at Remote Distances

Cited by in corpus (9)

• Locally and globally chiral fields for ultimate control of chiral light matter interaction
• Transient gain from $N_2^{+}$ in light filaments
• A systematic construction of Gaussian basis sets for the description of laser field ionization and high-harmonic generation
• Formation, stability, and highly nonlinear optical response of excitons to intense light fields interacting with two-dimensional materials
• Evidence of ac-Stark-shifted resonances in intense two-color circularly polarized laser fields
• Intrapulse Impact Processes in Dense-Gas Femtosecond Laser Filamentation
• Pump-probe study of plasma dynamics in gas-filled photonic crystal fiber using counter-propagating solitons
• Ionization Induced by the Ponderomotive Force in Intense and High-Frequency Laser Fields
• Modifications of filament spectra by shaped octave-spanning laser pulses