Conditions for perfect circular polarization of high-order harmonics driven by bichromatic counter-rotating laser fields

John Heslar, Dmitry A. Telnov, Shih I. Chu

Research output

Abstract

Recently, studies of high-order harmonic generation (HHG) from atoms driven by bichromatic counter-rotating circularly polarized laser fields have received considerable attention for this process could be a potential source of coherent circularly polarized extreme ultraviolet (XUV) and soft-x-ray beams in a tabletop-scale setup. In this paper, we address the problem with molecular targets and perform a detailed quantum study of the H2+ molecule in bichromatic (ω0, 2ω0) counter-rotating circular polarized laser fields where we adopt wavelengths (790 and 395 nm) and intensities (2×1014W/cm2) reported in a recent experiment [K. M. Dorney et al., Phys. Rev. Lett. 119, 063201 (2017)PRLTAO0031-900710.1103/PhysRevLett.119.063201]. Here, we demonstrate appropriate conditions to produce perfectly circular polarized harmonics. The calculated radiation spectrum contains doublets of left and right circularly polarized harmonics which display perfect circular polarization with use of the trapezoidal pulse shape, and substantial deviations from perfect circular polarization with use of the sine-squared pulse shape. We also study in detail short- and long-cycle counter-rotating circularly polarized driving pulses with a time delay between the two driving fields, ω0 and 2ω0. These time delayed circularly polarized driving pulses are applied to H atoms and H2+ molecules, and in both atomic and molecular cases we conclude a zero time delay corresponds to the highest HHG intensity for short pulses. For longer pulses there are no distinct differences in HHG intensities between the zero and nonzero time delays if the latter are within a few optical cycles of the fundamental frequency.

Original languageEnglish
Article number023419
Number of pages11
JournalPhysical Review A
Volume99
Issue number2
DOIs
Publication statusPublished - 15 Feb 2019

Fingerprint

circular polarization
counters
harmonics
pulses
lasers
harmonic generations
time lag
cycles
radiation spectra
atoms
molecules
deviation
wavelengths
x rays

Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

@article{4bafe8691aa248f987f2248d4a465c91,
title = "Conditions for perfect circular polarization of high-order harmonics driven by bichromatic counter-rotating laser fields",
abstract = "Recently, studies of high-order harmonic generation (HHG) from atoms driven by bichromatic counter-rotating circularly polarized laser fields have received considerable attention for this process could be a potential source of coherent circularly polarized extreme ultraviolet (XUV) and soft-x-ray beams in a tabletop-scale setup. In this paper, we address the problem with molecular targets and perform a detailed quantum study of the H2+ molecule in bichromatic (ω0, 2ω0) counter-rotating circular polarized laser fields where we adopt wavelengths (790 and 395 nm) and intensities (2×1014W/cm2) reported in a recent experiment [K. M. Dorney et al., Phys. Rev. Lett. 119, 063201 (2017)PRLTAO0031-900710.1103/PhysRevLett.119.063201]. Here, we demonstrate appropriate conditions to produce perfectly circular polarized harmonics. The calculated radiation spectrum contains doublets of left and right circularly polarized harmonics which display perfect circular polarization with use of the trapezoidal pulse shape, and substantial deviations from perfect circular polarization with use of the sine-squared pulse shape. We also study in detail short- and long-cycle counter-rotating circularly polarized driving pulses with a time delay between the two driving fields, ω0 and 2ω0. These time delayed circularly polarized driving pulses are applied to H atoms and H2+ molecules, and in both atomic and molecular cases we conclude a zero time delay corresponds to the highest HHG intensity for short pulses. For longer pulses there are no distinct differences in HHG intensities between the zero and nonzero time delays if the latter are within a few optical cycles of the fundamental frequency.",
keywords = "EXTREME-ULTRAVIOLET, GENERATION",
author = "John Heslar and Telnov, {Dmitry A.} and Chu, {Shih I.}",
year = "2019",
month = "2",
day = "15",
doi = "10.1103/PhysRevA.99.023419",
language = "English",
volume = "99",
journal = "Physical Review A - Atomic, Molecular, and Optical Physics",
issn = "1050-2947",
publisher = "American Physical Society",
number = "2",

}

TY - JOUR

T1 - Conditions for perfect circular polarization of high-order harmonics driven by bichromatic counter-rotating laser fields

AU - Heslar, John

AU - Telnov, Dmitry A.

AU - Chu, Shih I.

PY - 2019/2/15

Y1 - 2019/2/15

N2 - Recently, studies of high-order harmonic generation (HHG) from atoms driven by bichromatic counter-rotating circularly polarized laser fields have received considerable attention for this process could be a potential source of coherent circularly polarized extreme ultraviolet (XUV) and soft-x-ray beams in a tabletop-scale setup. In this paper, we address the problem with molecular targets and perform a detailed quantum study of the H2+ molecule in bichromatic (ω0, 2ω0) counter-rotating circular polarized laser fields where we adopt wavelengths (790 and 395 nm) and intensities (2×1014W/cm2) reported in a recent experiment [K. M. Dorney et al., Phys. Rev. Lett. 119, 063201 (2017)PRLTAO0031-900710.1103/PhysRevLett.119.063201]. Here, we demonstrate appropriate conditions to produce perfectly circular polarized harmonics. The calculated radiation spectrum contains doublets of left and right circularly polarized harmonics which display perfect circular polarization with use of the trapezoidal pulse shape, and substantial deviations from perfect circular polarization with use of the sine-squared pulse shape. We also study in detail short- and long-cycle counter-rotating circularly polarized driving pulses with a time delay between the two driving fields, ω0 and 2ω0. These time delayed circularly polarized driving pulses are applied to H atoms and H2+ molecules, and in both atomic and molecular cases we conclude a zero time delay corresponds to the highest HHG intensity for short pulses. For longer pulses there are no distinct differences in HHG intensities between the zero and nonzero time delays if the latter are within a few optical cycles of the fundamental frequency.

AB - Recently, studies of high-order harmonic generation (HHG) from atoms driven by bichromatic counter-rotating circularly polarized laser fields have received considerable attention for this process could be a potential source of coherent circularly polarized extreme ultraviolet (XUV) and soft-x-ray beams in a tabletop-scale setup. In this paper, we address the problem with molecular targets and perform a detailed quantum study of the H2+ molecule in bichromatic (ω0, 2ω0) counter-rotating circular polarized laser fields where we adopt wavelengths (790 and 395 nm) and intensities (2×1014W/cm2) reported in a recent experiment [K. M. Dorney et al., Phys. Rev. Lett. 119, 063201 (2017)PRLTAO0031-900710.1103/PhysRevLett.119.063201]. Here, we demonstrate appropriate conditions to produce perfectly circular polarized harmonics. The calculated radiation spectrum contains doublets of left and right circularly polarized harmonics which display perfect circular polarization with use of the trapezoidal pulse shape, and substantial deviations from perfect circular polarization with use of the sine-squared pulse shape. We also study in detail short- and long-cycle counter-rotating circularly polarized driving pulses with a time delay between the two driving fields, ω0 and 2ω0. These time delayed circularly polarized driving pulses are applied to H atoms and H2+ molecules, and in both atomic and molecular cases we conclude a zero time delay corresponds to the highest HHG intensity for short pulses. For longer pulses there are no distinct differences in HHG intensities between the zero and nonzero time delays if the latter are within a few optical cycles of the fundamental frequency.

KW - EXTREME-ULTRAVIOLET

KW - GENERATION

UR - http://www.scopus.com/inward/record.url?scp=85061554971&partnerID=8YFLogxK

U2 - 10.1103/PhysRevA.99.023419

DO - 10.1103/PhysRevA.99.023419

M3 - Article

AN - SCOPUS:85061554971

VL - 99

JO - Physical Review A - Atomic, Molecular, and Optical Physics

JF - Physical Review A - Atomic, Molecular, and Optical Physics

SN - 1050-2947

IS - 2

M1 - 023419

ER -