Reading today…

Reading today…

Synthetic electromagnetic knot in a three-dimensional skyrmion

Science Advances  02 Mar 2018: Vol. 4, no. 3, eaao3820

Classical electromagnetism and quantum mechanics are both central to the modern understanding of the physical world and its ongoing technological development. Quantum simulations of electromagnetic forces have the potential to provide information about materials and systems that do not have conveniently solvable theoretical descriptions, such as those related to quantum Hall physics, or that have not been physically observed, such as magnetic monopoles. However, quantum simulations that simultaneously implement all of the principal features of classical electromagnetism have thus far proved elusive. We experimentally realize a simulation in which a charged quantum particle interacts with the knotted electromagnetic fields peculiar to a topological model of ball lightning. These phenomena are induced by precise spatiotemporal control of the spin field of an atomic Bose-Einstein condensate, simultaneously creating a Shankar skyrmion—a topological excitation that was theoretically predicted four decades ago but never before observed experimentally. Our results reveal the versatile capabilities of synthetic electromagnetism and provide the first experimental images of topological three-dimensional skyrmions in a quantum system.

DOI: 10.1126/sciadv.aao3820
Real-time spectral characterization of a photon pair source using a chirped supercontinuum seed

Real-time spectral characterization of a photon pair source using a chirped supercontinuum seed

New article in Optics Letters.

Jennifer Erskine, Duncan England, Connor Kupchak, and Benjamin Sussman

Optics Letters Vol. 43, Issue 4, pp. 907-910 (2018)

https://doi.org/10.1364/OL.43.000907

Photon pair sources have wide ranging applications in a variety of quantum photonic experiments and protocols. Many of these protocols require well controlled spectral correlations between the two output photons. However, due to low cross-sections, measuring the joint spectral properties of photon pair sources has historically been a challenging and time-consuming task. Here, we present an approach for the real-time measurement of the joint spectral properties of a fiber-based four wave mixing source. We seed the four wave mixing process using a broadband chirped pulse, studying the stimulated process to extract information regarding the spontaneous process. In addition, we compare stimulated emission measurements with the spontaneous process to confirm the technique’s validity. Joint spectral measurements have taken many hours historically and several minutes with recent techniques. Here, measurements have been demonstrated in 5–30 s depending on resolution, offering substantial improvement. Additional benefits of this approach include flexible resolution, large measurement bandwidth, and reduced experimental overhead.

 

Reading today…

Reading today…

Communication: Gas-phase structural isomer identification by Coulomb explosion of aligned molecules

The Journal of Chemical Physics 148, 091102 (2018); https://doi.org/10.1063/1.5023441
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

Reading today…

Reading today…

Linac Coherent Light Source: The first five years

Christoph Bostedt, Sébastien Boutet, David M. Fritz, Zhirong Huang, Hae Ja Lee, Henrik T. Lemke, Aymeric Robert, William F. Schlotter, Joshua J. Turner, and Garth J. Williams

Rev. Mod. Phys. 88, 015007 – Published 9 March 2016

A new scientific frontier opened in 2009 with the start of operations of the world’s first x-ray free-electron laser (FEL), the Linac Coherent Light Source (LCLS), at SLAC National Accelerator Laboratory. LCLS provides femtosecond pulses of x rays (270 eV to 11.2 keV) with very high peak brightness to access new domains of ultrafast x-ray science. This article presents the fundamental FEL physics and outlines the LCLS source characteristics along with the experimental challenges, strategies, and instrumentation that accompany this novel type of x-ray source. The main part of the article reviews the scientific achievements since the inception of LCLS in the five primary areas it serves: atomic, molecular, and optical physics; condensed matter physics; matter in extreme conditions; chemistry and soft matter, and biology.

DOI: 10.1103/RevModPhys.88.015007 

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.