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Title: High Harmonic Radiation Generation and Attosecond pulse generation from Intense Laser-Solid Interactions

Abstract

We have studied ion motion effects in high harmonic generation, including shifts to the harmonics which result in degradation of the attosecond pulse train, and how to mitigate them. We have examined the scaling with intensity of harmonic emission. We have also switched the geometry of the interaction to measure, for the first time, harmonics from a normal incidence interaction. This was performed by using a special parabolic reflector with an on axis hole and is to allow measurements of the attosecond pulses using standard techniques. Here is a summary of the findings: First high harmonic generation in laser-solid interactions at 10 21 Wcm -2, demonstration of harmonic focusing, study of ion motion effects in high harmonic generation in laser-solid interactions, and demonstration of harmonic amplification.

Authors:
 [1];  [1]
  1. Univ. of Michigan, Ann Arbor, MI (United States)
Publication Date:
Research Org.:
Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1322280
Report Number(s):
DOE-UMICH-0008352
UM#12-PAF06540/F031327
DOE Contract Number:
SC0008352
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY

Citation Formats

Thomas, Alexander Roy, and Krushelnick, Karl. High Harmonic Radiation Generation and Attosecond pulse generation from Intense Laser-Solid Interactions. United States: N. p., 2016. Web. doi:10.2172/1322280.
Thomas, Alexander Roy, & Krushelnick, Karl. High Harmonic Radiation Generation and Attosecond pulse generation from Intense Laser-Solid Interactions. United States. doi:10.2172/1322280.
Thomas, Alexander Roy, and Krushelnick, Karl. 2016. "High Harmonic Radiation Generation and Attosecond pulse generation from Intense Laser-Solid Interactions". United States. doi:10.2172/1322280. https://www.osti.gov/servlets/purl/1322280.
@article{osti_1322280,
title = {High Harmonic Radiation Generation and Attosecond pulse generation from Intense Laser-Solid Interactions},
author = {Thomas, Alexander Roy and Krushelnick, Karl},
abstractNote = {We have studied ion motion effects in high harmonic generation, including shifts to the harmonics which result in degradation of the attosecond pulse train, and how to mitigate them. We have examined the scaling with intensity of harmonic emission. We have also switched the geometry of the interaction to measure, for the first time, harmonics from a normal incidence interaction. This was performed by using a special parabolic reflector with an on axis hole and is to allow measurements of the attosecond pulses using standard techniques. Here is a summary of the findings: First high harmonic generation in laser-solid interactions at 1021 Wcm-2, demonstration of harmonic focusing, study of ion motion effects in high harmonic generation in laser-solid interactions, and demonstration of harmonic amplification.},
doi = {10.2172/1322280},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 9
}

Technical Report:

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  • A comprehensive analysis is presented which describes the generation of harmonic radiation by the stimulated backscattering of intense laser fields from electron beams and from plasmas. The dynamics of the intense laser-electron interaction are analyzed using a fully nonlinear, relativistic cold fluid model valid to all orders in the amplitude of the pump laser. In general. the back-scattered radiation, from an electron beam or stationary plasma, occurs at odd harmonics of the doppler shifted incident laser frequency. The strength of the harmonics is strongly dependent on the incident laser intensity. The growth rate and saturation level of the backscattered harmonicsmore » are calculated and limitations due to thermal, space charge and collisional effects are discussed. Significant radiation generation at high harmonics requires sufficiently intense pump laser fields and sufficiently cold axial electron distributions. This mechanism may provide a practical method for producing coherent radiation in the XUV regime.« less
  • In the present work, laser-parameter effects on the isolated attosecond pulse generation from two-color high-order harmonic generation (HHG) process are theoretically investigated by use of a wave-packet dynamics method. A 6-fs, 800-nm, 6x10{sup 14}W/cm{sup 2}, linearly polarized laser pulse serves as the fundamental driving pulse and parallel linearly polarized control pulses at 400 nm (second harmonic) and 1600 nm (half harmonic) are superimposed to create a two-color field. Of the two techniques, we demonstrate that using a half-harmonic control pulse with a large relative strength and zero phase shift relative to the fundamental pulse is a more promising way tomore » generate the shortest attosecond pulses. As a consequence, an isolated 12-as pulse is obtained by Fourier transforming an ultrabroad xuv continuum of 300 eV in the HHG spectrum under half-harmonic control scheme when the relative strength {radical}(R)=0.6 and relative phase =0.« less
  • High order harmonic generation from solid targets is a compelling route to generating intense attosecond or even zeptosecond pulses. However, the effects of ion motion on the generation of harmonics have only recently started to be considered. Here, we study the effects of ion motion in harmonics production at ultrahigh laser intensities interacting with solid density plasma. Using particle-in-cell simulations, we find that there is an optimum density for harmonic production that depends on laser intensity, which scales linearly with a{sub 0} with no ion motion but with a reduced scaling if ion motion is included. We derive a scalingmore » for this optimum density with ion motion and also find that the background ion motion induces Doppler red-shifts in the harmonic structures of the reflected pulse. The temporal structure of the Doppler shifts is correlated to the envelope of the incident laser pulse. We demonstrate that by introducing a frequency chirp in the incident pulse we are able to eliminate these Doppler shifts almost completely.« less