Quantum Beat Photoelectron Imaging Spectroscopy of Xe in the VUV

Quantum Beat Photoelectron Imaging Spectroscopy of Xe in the VUV

UPDATE June 2018 – Now published in Phys. Rev. A 97, 063417, 2018, DOI: 10.1103/PhysRevA.97.063417

… and in Kaleidoscope.

March 2018: New on arXiv

Time-resolved pump-probe measurements of Xe, pumped at 133~nm and probed at 266~nm, are presented. The pump pulse prepared a long-lived hyperfine wavepacket, in the Xe 5p5(2P1/2)6s 2[1/2]1 manifold (E=77185 cm1=9.57 eV). The wavepacket was monitored via single-photon ionization, and photoelectron images measured. The images provide angle- and time-resolved data which, when obtained over a large time-window (900~ps), constitute a precision quantum beat spectroscopy measurement of the hyperfine state splittings. Additionally, analysis of the full photoelectron image stack provides a quantum beat imaging modality, in which the Fourier components of the photoelectron images correlated with specific beat components can be obtained. This may also permit the extraction of isotope-resolved photoelectron images in the frequency domain, in cases where nuclear spins (hence beat components) can be uniquely assigned to specific isotopes (as herein), and also provides phase information. The information content of both raw, and inverted, image stacks is investigated, suggesting the utility of the Fourier analysis methodology in cases where images cannot be inverted.

Also available on Authorea.

Full data, code & analysis notes on OSF.

Reading today…

Reading today…

Relativistic and QED Effects in the Fundamental Vibration of T2

T. Madhu Trivikram, M. Schlösser, W. Ubachs, and E. J. Salumbides

Phys. Rev. Lett. 120, 163002 – Published 16 April 2018

The hydrogen molecule has become a test ground for quantum electrodynamical calculations in molecules. Expanding beyond studies on stable hydrogenic species to the heavier radioactive tritium-bearing molecules, we report on a measurement of the fundamental T2 vibrational splitting (v=01) for J=05 rotational levels. Precision frequency metrology is performed with high-resolution coherent anti-Stokes Raman spectroscopy at an experimental uncertainty of 10–12 MHz, where sub-Doppler saturation features are exploited for the strongest transition. The achieved accuracy corresponds to a 50-fold improvement over a previous measurement, and it allows for the extraction of relativistic and QED contributions to T2 transition energies.

Quantum Metrology with Photoelectrons (book)

Quantum Metrology with Photoelectrons (book)

Update April 2018 – the books are now available via IOP, see details at end of post.

Book for IOP Concise Physics series, due early 2018

Dr. Paul Hockett

National Research Council of Canada

Online resources

OSF project (ID: q2v3g) with interactive content and additional resources, DOI: 10.17605/OSF.IO/Q2V3G

femtolab.ca website, posts tagged “metrology-book”

femtolab.ca website, posts tagged “video”

Abstract

Photoionization is an interferometric process, in which multiple paths can contribute to the final continuum photoelectron wavefunction. At the simplest level, interferences between different final angular momentum states are manifest in the energy and angle resolved photoelectron spectra: metrology schemes making use of these interferograms are thus phase-sensitive, and provide a powerful route to detailed understanding of photoionization. In these cases, the continuum wavefunction (and underlying scattering dynamics) can be characterised. At a more complex level, such measurements can also provide a powerful probe for other processes of interest, leading to a more general class of quantum metrology built on phase-sensitive photoelectron imaging.  Since the turn of the century, the increasing availability of photoelectron imaging experiments, along with the increasing sophistication of experimental techniques, and the availability of computational resources for analysis and numerics, has allowed for significant developments in such photoelectron metrology.

Volume I covers the core physics of photoionization, including a range of computational examples. The material is presented as both reference and tutorial, and should appeal to readers of all levels.  Volume II explores applications, and the development of quantum metrology schemes based on photoelectron measurements. The material is more technical, and will appeal more to the specialist reader.

Full text

Quantum Metrology with Photoelectrons

Volume 1
ISBN 978-1-6817-4684-5
http://iopscience.iop.org/book/978-1-6817-4684-5
Volume 2
ISBN 978-1-6817-4688-3
http://iopscience.iop.org/book/978-1-6817-4688-3

 

Bootstrapping (Ultrafast) Photoionization Dynamics – PQE 2018 (extended) video

Bootstrapping (Ultrafast) Photoionization Dynamics – PQE 2018 (extended) video

Bootstrapping (Ultrafast) Photoionization Dynamics – PQE 2018 (extended) from femtolab.ca on Vimeo.

Talk originally given as a 20min presentation at PQE 2018 (Snowbird, Utah, http://pqeconference.com/pqe2018/program). The original talk was not recorded; this is an extended version using the same slides, but with rather more introductory discussion. The abstract is given below, along with links to additional material.

More details of the work discussed in the main part of the talk can be found in:
Molecular Frame Reconstruction Using Time-Domain Photoionization Interferometry.
Marceau et. al., Physical Review Letters, 119(8), 83401 (2017).
http://doi.org/10.1103/PhysRevLett.119.083401

PQE 2018 Abstract

Bootstrapping (Ultrafast) Photoionization Dynamics
Slot: Tuesday Morning Invited Session 1
Session: Ultrafast photoionization dynamics

Photoionization is an interferometric process, in which multiple paths can contribute to the final continuum photoelectron state. At the simplest level, interferences between different final angular momentum states are clearly manifest in the energy and angle resolved photoelectron spectra; metrology schemes making use of these interferograms are thus phase-sensitive, and provide a powerful route to detailed understanding of photoionization.

The high information content of angle-resolved interferograms, combined with geometric control over the photoionization dynamics, can provide sufficient data for reconstruction of the continuum state, in terms of the constituent partial waves and phases. This has recently been explored for a range of cases, including the use of ultrafast pump-probe schemes with a bootstrapping analysis methodology: aspects of this work will be presented.

DOI: 10.6084/m9.figshare.5645509

Refs
Molecular Frame Reconstruction Using Time-Domain Photoionization Interferometry
Marceau, C., Makhija, V., Platzer, D., Naumov, A. Y., Corkum, P. B., Stolow, A., Villeneuve, D. M., Hockett, P. (2017). Physical Review Letters, 119(8), 83401. http://doi.org/10.1103/PhysRevLett.119.083401

Coherent control of photoelectron wavepacket angular interferograms.
Hockett, P., Wollenhaupt, M., & Baumert, T. (2015). Journal of Physics B: Atomic, Molecular and Optical Physics, 48(21), 214004. http://doi.org/10.1088/0953-4075/48/21/214004

Complete Photoionization Experiments via Ultrafast Coherent Control with Polarization Multiplexing.
Hockett, P., Wollenhaupt, M., Lux, C., & Baumert, T. (2014). Physical Review Letters, 112(22), 223001. http://doi.org/10.1103/PhysRevLett.112.223001

Coherent imaging of an attosecond electron wave packet.
Villeneuve, D. M., Hockett, P., Vrakking, M. J. J., & Niikura, H. (2017). Science, 356(6343), 1150–1153. http://doi.org/10.1126/science.aam8393

Bootstrapping to the Molecular Frame with Time-domain Photoionization Interferometry

Bootstrapping to the Molecular Frame with Time-domain Photoionization Interferometry

Update Jan 2018 – a presentation covering this work was given at the PQE conference, video and slides are available online.

Update August 2017 – this article is now published in PRL, under the alternative title Molecular Frame Reconstruction Using Time-Domain Photoionization Interferometry.
Phys. Rev. Lett. 119, 083401 (2017), DOI: 10.1103/PhysRevLett.119.083401

(Feb 2017) New manuscript on the arxiv:

Bootstrapping to the Molecular Frame with Time-domain Photoionization Interferometry

 

Photoionization of molecular species is, essentially, a multi-path interferometer with both experimentally controllable and intrinsic molecular characteristics. In this work, XUV photoionization of impulsively aligned molecular targets (N2) is used to provide a time-domain route to “complete” photoionization experiments, in which the rotational wavepacket controls the geometric part of the photoionization interferometer. The data obtained is sufficient to determine the magnitudes and phases of the ionization matrix elements for all observed channels, and to reconstruct molecular frame interferograms from lab frame measurements. In principle this methodology provides a time-domain route to complete photoionization experiments, and the molecular frame, which is generally applicable to any molecule (no prerequisites), for all energies and ionization channels.

arxiv 1701.08432 (2017)

Supplementary material (theory, data and code) available at DOI: 10.6084/m9.figshare.4480349.

Photoionization Interferometry & Metrology

Photoionization Interferometry & Metrology

Photoionization is a complex quantum mechanical process, with a range of interfering channels playing a role in even the simplest case. For problems in quantum metrology and sensing, a detailed understanding of the process is desirable for accurate measurements; quantum control is also a possible outcome of such understanding. New research in this area will build on recent cutting-edge work at NRC (see below), which probed the fundamental quantum physics of photoionization in atoms and molecules, and metrology work which demonstrated the retrieval of electron wavefunctions via interferometric time-domain measurements.

Four areas of photoionization interferometry are the target of current research:

  1. Metrology and control with rotational wavepackets.
  2. Metrology and control with shaped laser pulses.
  3. Quantum dynamics probed via photoionization interferometry.
  4. Fundamental properties of photoion and photoelectron coherence.

Depending on interests and experience, project work will be in one (or more) of these areas.

An introduction to this topic, and recent work, can be found in Paul’s DAMOP 2017 talk Phase-sensitive Photoelectron Metrology (below), and via our blog.

Phase-sensitive Photoelectron Metrology – Dr. P. Hockett, presentation at DAMOP 2017 from femtolab.ca on Vimeo.

Angle-resolved RABBIT: theory and numerics

Angle-resolved RABBIT: theory and numerics

Update 28/06/17 – Now published in J. Phys. B, special issue on Correlations in Light-Matter Interactions.

New manuscript:

Angle-resolved RABBIT: theory and numerics

P. Hockett

Angle-resolved (AR) RABBIT measurements offer a high information content measurement scheme, due to the presence of multiple, interfering, ionization channels combined with a phase-sensitive observable in the form of angle and time-resolved photoelectron interferograms. In order to explore the characteristics and potentials of AR-RABBIT, a perturbative 2-photon model is developed; based on this model, example AR-RABBIT results are computed for model and real systems, for a range of RABBIT schemes. These results indicate some of the phenomena to be expected in AR-RABBIT measurements, and suggest various applications of the technique in photoionization metrology.

Paul Hockett 2017 J. Phys. B: At. Mol. Opt. Phys. 50 154002

Pre-print available via Authorea, DOI: 10.22541/au.149037518.89916908.

arXiv 1703.08586 (2017) 

See also the recent AR-RABBIT presentation for a brief intro to this topic.