Classical effect for enhanced high harmonic yield in ultrashort laser pulses with a moderate laser intensity

  title={Classical effect for enhanced high harmonic yield in ultrashort laser pulses with a moderate laser intensity},
  author={Y Z Shi and S. Wang and Fulong Dong and Y. Li and Y. J. Chen},
  journal={Journal of Physics B: Atomic, Molecular and Optical Physics},
  • Y. Z. ShiS. Wang Y. J. Chen
  • Published 15 September 2015
  • Physics
  • Journal of Physics B: Atomic, Molecular and Optical Physics
We study the influence of pulse duration on high harmonic generation (HHG) by exploring a wide laser-parameter region theoretically. Previous studies have shown that for high laser intensities close to saturation ionization intensity, the HHG inversion efficiency is higher for shorter pulses since the ground-state depletion is weaker in short pulses. Our simulations show that this high efficiency also appears for a moderate laser intensity at which the ionization is not very strong. A classical… 

High-order harmonic generation with a single-color mid-infrared laser field by frequency-chirping

By numerically solving the time-dependent Schrödinger equation for helium atoms in a single mid-infrared laser field, we explore the frequency-chirping effect of laser field on high-order harmonic

Time-resolved harmonic emission from aligned molecules in orthogonal two-color fields

We study the spectral and temporal properties of high-order harmonic generation (HHG) from aligned molecules in orthogonal two-color laser fields consisting of a strong fundamental field and its

Regulating the higher harmonic cutoffs via sinc pulse

We theoretically investigate the generation of higher harmonics and the construction of a single attosecond pulse (ASP) by means of two oppositely polarized sinc-shaped driver pulses. In comparison

Introducing an effective method for extending the high harmonic spectrum plateau from gas targets

An effective semi-classical method is introduced for controlling the high-order harmonic generation process and extending the cutoff frequency. This method is capable of defining the proper

High ellipticity of harmonics from molecules in strong laser fields of small ellipticity

We study high-order harmonic generation (HHG) from aligned molecules in strong elliptically polarized laser fields numerically and analytically. Our simulations show that the spectra and polarization

Two-Color Attosecond Chronoscope


A Robust Scaling up Method of Output Energy and Photon Energy on High-Order Harmonic Generation: towards Sub-μJ Water Window Soft X-Rays

Nano-joule class water-window high-order harmonic generation under a neutral-medium condition is presented. The maximum harmonic photon energy reaches 360 eV with 3.5-nJ/shot in the water-window

Exterior time scaling with the stiffness-free Lanczos time propagator: Formulation and application to atoms interacting with strong midinfrared lasers

Aiming at efficient numerical treatment of tunneling ionization of atoms and molecules by mid-infrared (IR) lasers, exterior time scaling (ETS) theory is formulated as a generalization of the



Nonadiabatic Effects in High-Harmonic Generation with Ultrashort Pulses.

It is observed that the harmonic spectrum of argon taken with laser pulses contains harmonics up to 20 orders higher than for 100 fs laser pulses with the intensity, and it is shown that this increase in harmonics is because the atom survives to intensities.

Phase-dependent harmonic emission with ultrashort laser pulses

We consider harmonic generation by atoms exposed to an intense laser pulse of a few femtoseconds. Our results, obtained by solving numerically the corresponding three-dimensional time-dependent

Attosecond Synchronization of High-Harmonic Soft X-rays

It is shown that the synchronization could be improved considerably by controlling the underlying ultrafast electron dynamics, to provide pulses of 130 attoseconds in duration, which would allow us to track fast electron processes in matter.

High-Harmonic Generation of Attosecond Pulses in the ``Single-Cycle'' Regime

High-harmonic generation with excitation pulses shorter than 25fs is studied theoretically using a 3D model. For very short excitation pulses, a new regime of harmonic generation by a

Enhanced phase-matching for generation of soft X-ray harmonics and attosecond pulses in atomic gases.

It is shown that the coherence length dictated by ionization-induced dephasing does not constitute an ultimate limitation to the coherent growth of soft X-ray (> 100 eV) harmonics driven by few-cycle mid-IR driving pulses: perfect phase-matching, similar to non-adiabatic self-phase- matching, can be achieved even without non-linear deformation of the driving pulse.

Attosecond pulse trains generated using two color laser fields.

The spectral and temporal structure of high harmonic emission from argon exposed to an infrared laser field and its second harmonic is investigated and the generation of phase stabilized few cycle pulses to the extreme ultraviolet regime is extended.

Wavelength scaling of high harmonic generation efficiency.

An experimental study of the high harmonic yield over a wavelength range of 800-1850 nm found that the scaling at constant laser intensity is lambda(-6.3+/-1.1) in Xe and lambda(-(5-6)) in Kr over the wavelength range, somewhat worse than the theoretical predictions.

Probing the spectral and temporal structures of high-order harmonic generation in intense laser pulses

We present an ab initio three-dimensional quantum study of high-order harmonic generation ~HHG! of atomic H in intense pulsed laser fields. Accurate time-dependent wave functions are obtained by

Characterizing isolated attosecond pulses from hollow-core waveguides using multi-cycle driving pulses

The generation of attosecond-duration light pulses using the high-order harmonic generation process is a rapidly evolving area of research. In this work, we combine experimental measurements with

Quasi-phase matching of high-harmonics and attosecond pulses in modulated waveguides.

A corrugated hollow-core fiber modulates the intensity of the fundamental pulse along the direction of propagation, resulting in a periodic modulation of the harmonic emission at wavelengths close to the cutoff, increasing the harmonic yield by up to three orders of magnitude.