Time-bin-to-polarization conversion of ultrafast photonic qubits

Time-bin-to-polarization conversion of ultrafast photonic qubits

Connor Kupchak, Philip J. Bustard, Khabat Heshami, Jennifer Erskine, Michael Spanner, Duncan G. England, and Benjamin J. Sussman
Phys. Rev. A 96, 053812 – Published 6 November 2017

The encoding of quantum information in photonic time-bin qubits is apt for long-distance quantum communication schemes. In practice, due to technical constraints such as detector response time, or the speed with which copolarized time-bins can be switched, other encodings, e.g., polarization, are often preferred for operations like state detection. Here, we present the conversion of qubits between polarization and time-bin encodings by using a method that is based on an ultrafast optical Kerr shutter and attain efficiencies of 97% and an average fidelity of 0.827±0.003 with shutter speeds near 1 ps. Our demonstration delineates an essential requirement for the development of hybrid and high-rate optical quantum networks.

Quantum Metrology with Photoelectrons (book)

Quantum Metrology with Photoelectrons (book)

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

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: this book aims to discuss the fundamental concepts along with recent and emerging applications.

 

Bootstrapping to the Molecular Frame with Time-domain Photoionization Interferometry

Bootstrapping to the Molecular Frame with Time-domain Photoionization Interferometry

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.

Trans jacket inscription of FBGs

Trans jacket inscription of FBGs

Using pulses from the 30fs amplified laser system in the femtolabs, and fibre writing equipment from the Fibre Photonics lab, this project focusses on developing methods for inscription of Fibre Bragg Gratings (FBGs) through the polyimide fibre cover. Through the use of short focal length acylindrical optics, the laser spot-size on the cover is much larger than in the core. This along with the very short pulses allows us to work in a regime where we can still write strong gratings through multiphoton dielectric modification, without damaging the cover (through two photon absorption).

Direct Ion Detection & Detector Technology Development

Direct Ion Detection & Detector Technology Development

Our VIRP chamber (for rapid vacuum instrument prototyping), is designed to perform experiments with new detector technologies, and provide a route to optimising the methodologies and technologies. Early work has been based around novel scintillators recently developed in Oxford [1,2], and also involved trialling the PImMS camera (for 3D ion imaging) for ultrafast pump-probe experiments [3] – see our blog for further information. New project work will continue to build in these directions.

[1] A new detector for mass spectrometry: Direct detection of low energy ions using a multi-pixel photon counter
Edward S. Wilman, Sara H. Gardiner, Andrei Nomerotski, Renato Turchetta, Mark Brouard and Claire Vallance
Rev. Sci. Instrum. 83, 013304 (2012).

[2] Improved direct detection of low-energy ions using a multipixel photon counter coupled with a novel scintillator
Winter, King, Brouard & Vallance
International Journal of Mass Spectrometry, 397–398, 27–31 (2016)

[3] Time-resolved multi-mass ion imaging: femtosecond UV-VUV pump-probe spectroscopy with the PImMS camera
Ruaridh ForbesVarun MakhijaKévin VeyrinasAlbert StolowJason W. L. LeeMichael BurtMark BrouardClaire VallanceIain WilkinsonRune LaustenPaul Hockett
arXiv 1702.00744 (2017)The Journal of Chemical Physics 147, 013911 (2017), DOI: http://dx.doi.org/10.1063/1.4978923

 

 

Intense light-matter interactions for source development

Intense light-matter interactions for source development

Novel wave-mixing techniques can be used for the generation of ultrashort pulses in the VUV (<200nm) region of the spectrum.  This project will investigate the development of new light sources, based on our existing expertise and capabilities at 5th and 6th harmonic generation. These processes make use of a high-power 800nm femtosecond laser on the back-end, and involve multiple stages of non-linear wave-mixing in crystals and gases. The generation of tunable VUV is of particular interest.

For more on our work with VUV so far, see:
Time-resolved multi-mass ion imaging: femtosecond UV-VUV pump-probe spectroscopy with the PImMS camera
Ruaridh ForbesVarun MakhijaKévin VeyrinasAlbert StolowJason W. L. LeeMichael BurtMark BrouardClaire VallanceIain WilkinsonRune LaustenPaul Hockett
arXiv 1702.00744 (2017)The Journal of Chemical Physics 147, 013911 (2017), DOI: http://dx.doi.org/10.1063/1.4978923

 

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.