• Room 01.005 - Old Physics

    United Kingdom

20122020

Research output per year

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Personal profile

Research Interests

Recent advances in laser technology have facilitated the experimental analysis of atomic structure and electron dynamics in undprecedented detail. The process of harmonic generation in particular has been central to these advances both as a basis for ultrashort and high-energy laser pulses and as a tool for elucidating ultrafast dynamics. Typically, now, we are interested in dynamics which occur on the attosecond scale (1 as = 10-18 s), which is the fundamental time scale of electronic motion in the atom.

Theoretical methods capable of describing attosecond scale electronic motion typically adopt a classical approach where an electron is driven by a laser field in the net potential of the residual ion. However, methods pioneered at QUB allow us to address the interaction of all the electrons in an atomic system. It is these multielectron interactions which mediate ultrafast dynamics and thus it is imperative to address them accurately.

Time-dependent R-matrix (TDRM) theory, and the associated TDRM and RMT (R-matrix incorporating time dependence) codes, are among the only methods in the world capable of describing multielectron and multichannel effects in ultrafast laser atom interactions. For my PhD thesis I used the TDRM method to address harmonic generation-- the production of high frequency laser light via stimulated subcycle electron motion-- and uncovered a series of multielectron aspects to the process. For instance, interference bewteen electrons competing in the harmonic generation process can lead to an increase in the harmonic yield at particular frequencies.

I have since extended these studies of ultrafast processes to experimentally relevant (mid-IR) wavelengths. Now my research focuses on extracting experimental observables from the detailed ab-initio calculations performed with RMT. To this end I have investigated several cutting-edge experimental schemes using the RMT approach, including attosecond transient absorption spectroscopy, strong-field rescattering and, most recently, XUV initiated high harmonic generation.

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Projects

Research Output

Atomic and molecular suite of R-matrix codes for ultrafast dynamics in strong laser fields and electron/positron scattering

Wragg, J., Benda, J., Mašín, Z., Armstrong, G. S. J., Clarke, D. D. A., Brown, A. C., Ballance, C., Harvey, A. G., Houfek, K., Sunderland, A., Plummer, M., Gorfinkiel, J. D. & Van Der Hart, H., 11 Jun 2020, In : Journal of Physics: Conference Series. 1412, 7, 072017.

Research output: Contribution to journalLetter

Open Access
File
  • 6 Downloads (Pure)
    Open Access
    File
  • 6 Downloads (Pure)

    Electron correlation and short-range dynamics in attosecond angular streaking

    Armstrong, G. S. J., Clarke, D. D. A., Benda, J., Brown, A. C. & Van Der Hart, H., 17 Apr 2020, In : Physical Review A (Atomic, Molecular, and Optical Physics). 101, 4, 6 p., 041401(R).

    Research output: Contribution to journalArticle

    Open Access
    File
  • 39 Downloads (Pure)
  • 7 Citations (Scopus)
    Open Access
    File
  • 6 Citations (Scopus)
    211 Downloads (Pure)

    Datasets

    Electron correlation and short-range dynamics in attosecond angular streaking in the Fluorine anion

    Armstrong, G. (Creator), Brown, A. (Creator), Wragg, J. (Creator), Clarke, D. (Creator) & Van Der Hart, H. (Creator), Queen's University Belfast, 10 Apr 2020

    Dataset

    File
    File

    Extreme-ultraviolet-initiated High-harmonic Generation in Ar+

    Brown, A. (Supervisor), Clarke, D. (Creator) & Van Der Hart, H. (Supervisor), Queen's University Belfast, 09 Feb 2018

    Dataset

    File

    Cooper Minimum in PICS and HHG spectra in Ar+

    Brown, A. (Creator), Tyndall, N. (Creator) & Hassouneh, O. (Creator), Queen's University Belfast, 28 Aug 2018

    Dataset

    File

    Prizes

    Best Student Poster

    Brown, Andrew (Recipient), 23 Jul 2011

    Prize: Prize (including medals and awards)

    Best Student Speaker

    Brown, Andrew (Recipient), 28 Jun 2012

    Prize: Prize (including medals and awards)

    Activities

    • 9 Participation in conference
    • 3 Participation in workshop, seminar, course
    • 1 Participation in Festival/Exhibition

    Faraday discussion: Ultrafast imaging and photochemical dynamics

    Andrew Brown (Participant)

    31 Aug 201602 Sep 2016

    Activity: Participating in or organising an event typesParticipation in conference

    EU-COST Action: XLIC (XUV/X-ray light and fast ions for ultrafast chemistry)

    Andrew Brown (Invited speaker)

    30 Aug 2016

    Activity: Participating in or organising an event typesParticipation in conference

    Intel- preparing your software for Knight's Landing

    Andrew Brown (Participant)

    11 Feb 2016

    Activity: Participating in or organising an event typesParticipation in workshop, seminar, course

    AMIG: Atomic and Molecular Interactions Group

    Andrew Brown (Participant)

    31 May 2016

    Activity: Participating in or organising an event typesParticipation in conference

    ATTO 2015

    Andrew Brown (Participant)

    05 Jul 201510 Jul 2015

    Activity: Participating in or organising an event typesParticipation in conference

    Press / Media

    Mathsweek Ireland promotion 2016

    Daniel Dundas & Andrew Brown

    21/10/2016

    1 Media contribution

    Press/Media: Public Engagement Activities

    Thesis

    Ultrafast Atomic Dynamics in Arbitrary Light Fields

    Author: Clarke, D., Jul 2020

    Supervisor: Van Der Hart, H. (Supervisor) & Brown, A. (Supervisor)

    Student thesis: Doctoral ThesisDoctor of Philosophy