Light matter interaction

10:00 Vancouver – 11:00 Edmonton – 12:00 Winnipeg – 13:00 Montreal – 14:00 Halifax


Ksenia Dolgaleva

University of Ottawa, Ottawa, Ontario, Canada 

Light-Matter Interaction

Abstract: NSERC CREATE TrUST educational program is dedicated to ultrafast and THz optics and deals with a plethora of related phenomena. At the basis of all these phenomena, there is light-matter interaction and underlying effects. Specifically, low-intensity interaction reveals such properties of optical materials as absorption and material dispersion, while high-intensity interaction is associated with nonlinear optical effects. The presentation on “Light-Matter Interaction” intends to overview fundamental aspects of linear and nonlinear optical interaction of light with matter. The talk is designed to be easy to follow and accessible to students of all levels.



Soheil Zibod  

University of Ottawa, Ottawa, Ontario, Canada

THz Nonlinear Spectroscopy of Solids

Abstract: The study of terahertz (THz) region of electromagnetic spectrum has gained an increasing attention in the scientific fields of late, due to its broad applications in biology and biomedical sensing, security systems and non-destructive testing. The introduction of intense THz sources with electric field peak values as large as 1MV/cm has made the study of nonlinear behaviour of different materials possible. The talk on “THz Nonlinear Spectroscopy of Solids” aims to introduce a digestible knowledge in THz nonlinear spectroscopy; with which we are able to explore the nonlinear spectroscopy of solids at THz frequencies, from different angles.


THz spectroscopy

10:00 Vancouver – 11:00 Edmonton – 12:00 Winnipeg – 13:00 Montreal – 14:00 Halifax


David G. Cooke

Department of Physics, McGill University, Montreal, Quebéc, Canada 

Overview of Time-domain THz Spectroscopy Techniques



Nils Refvik 

Department of Physics, University of Alberta, Edmonton, Alberta, Canada

Probing ultrafast carrier dynamics in HgCdTe thin films with THz spectroscopy


Shiny and brilliant – Laser-plasma interactions for everyone

10:30 Vancouver – 11:30 Edmonton – 12:30 Winnipeg – 13:30 Montreal – 14:30 Halifax


Louise Willingale 

Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan, U.S.

Exploring extreme plasma physics with multi-Petawatt laser pulses

Abstract: State-of-the-art multi-Petawatt laser facilities coming online include the Zettawatt Equivalent Ultrashort pulse laser System (ZEUS), a user facility being commissioned at the University of Michigan. The 3-PW pulses will make ZEUS the highest power laser in the USA. This talk will describe the various experimental approaches that can be used to produce ultrashort particle beams and light-sources, as well as their application to study strong-field plasma physics and beyond. One area of interest is to create extremely strong magnetic fields within the hot plasma in the laboratory, so we can study the microphysics likely to be occurring around the most energetic objects in the universe

Bio: Louise Willingale is an Associate Professor at the University of Michigan in the Electrical and Computer Engineering department and the Associate Director for the NSF ZEUS facility at the Gérard Mourou Center for Ultrafast Optical Science. Prof. Willingale researches experimental high-intensity laser-plasma interactions, with a focus on relativistic electron heating, ion acceleration, proton radiography, magnetic-field generation, and reconnection. She received a MSci in Physics (2003) and a PhD in Plasma Physics (2007) from Imperial College London. In 2008, she moved to the University of Michigan, first as a Postdoctoral Researcher, then as an Assistant Research Scientist, before becoming an Assistant Professor in 2014. In 2018, she received a Faculty Early Career Development (CAREER) Award from the NSF to study laser-driven magnetic reconnection. In 2022 she was elected Fellow of the American Physical Society (APS), became a Kavli Fellow, and was a Co-chair for the Multi-Petawatt Physics Prioritization (MP3) workshop and report



Mangaljit Singh 

Institut National de la Recherche Scientifique (INRS), Énergie Matériaux Télécommunications Research Centre (EMT), Advanced Laser Light Source Laboratory (ALLS), Varennes, Quebéc, Canada

Resonant high-order harmonic generation from laser-ablated plumes

Abstract: High-order harmonic generation is a highly nonlinear process that takes place when an intense ultrashort laser pulse, typically of femtosecond temporal duration, interacts with a media. High-order harmonic generation provides a table-top coherent source of extreme ultraviolet pulses with femtosecond and attosecond temporal pulse duration. However, the low harmonic conversion efficiency from the widely used noble gases is a critical issue (typically 10-6-10-7), generating harmonic energy per pulse at the nJ scale. An alternate source for high-order harmonic generation providing high extreme ultraviolet photon flux is resonant harmonic generation from the laser-ablated plume, with a high conversion efficiency of 10-4, generating μJ-level harmonic energies per pulse. During the seminar, I will present our recent investigations conducted in the Advanced Laser Light Source laboratory at Institut National de la Recherche Scientifique – Énergie Matériaux Télécommunications (INRS – EMT) on high-order harmonic generation from laser-ablated plumes.

Bio: Mangaljit obtained his Master’s degree in Applied Optics from the Indian Institute of Technology Delhi, India in the year 2016. Subsequently, in 2021, he completed his doctoral degree at INRS-EMT, under the guidance of Professor Tsuneyuki Ozaki. Currently, Mangaljit serves as a Research Associate at INRS-EMT, working within the group led by Professor François Légaré. His research focuses on investigating the interaction between high-intensity ultrafast lasers and matter, with a particular emphasis on the coherent extreme ultraviolet radiation generated through high-order harmonic generation.


March 9th, 2022

Initiating collaboration between the European Extreme Light Infrastructure ELI and Canadian labs

10:30 Vancouver – 11:30 Edmonton – 12:30 Winnipeg – 13:30 Montreal – 14:30 Halifax


Allen Weeks

Director General, The Extreme Light Infrastructure ERIC, Dolní Břežany, Czech Republic

The Extreme Light Infrastructure: Unprecedented Access to Advanced Laser-Based Research Facilities

Abstract: The Extreme Light Infrastructure is among the world’s most advanced and diverse laser-based research infrastructures. The three ELI Facilities provide access to a very broad range of leading high-power, high-repetition-rate laser systems and secondary sources. Located in three different European countries, the labs include more than 700 scientists and staff from more than 40 different countries. An overview of the status of the facilities and the available offer to users will be presented. The ELI Facilities are in the process of ramping up the user programme and now, with the announcement of the 2nd Call. The current offer includes 5 primary laser systems and 10 secondary sources. The systems range from very short pulse (<10fs) kHz systems to petawatt class lasers. There are 11 end-stations and 6 stand-alone experimental platforms available. Areas of science include AMO, material science, condensed matter, surface science, cultural heritage, and nanoscience and much more. In addition to the user programme, ongoing commissioning activities will be presented as well as scientific initiatives

Bio: Allen Weeks is Director General at the Extreme Light Infrastructure (ELI), where he has been since 2017. In that time ELI has been established as a European Research Infrastructure Consortium and the leading European high-power laser infrastructure, with locations in the Czech Republic and Hungary. Before joining ELI, Weeks led the In-Kind Coordination programme at the European Spallation Source ERIC (ESS) where he managed the effort that brought together over 50 European institutions to deliver more than €550 million to construction the leading next generation spallation neutron source. Weeks began working with European and global research infrastructures in 2005, coordinating the FERMI free-electron laser project in Trieste, Italy. He has experience in industry, having served as Executive Director at Instrumentation Technologies for business development. He spent six years in the pharmaceutical industry.



Patrizio Antici 

Institut national de la recherche scientifique (INRS), Énergie Matériaux Télécommunications Research Centre (EMT), Varennes, Quebéc, Canada

Laser-accelerated secondary sources for material science applications

Abstract: The advent of high-power (TW) ultra-short (fs-ps) lasers has recently opened up the field of laser-driven plasma acceleration, which includes the acceleration of electrons, protons and X-rays. The investigation of these secondary sources and its use has triggered considereable investments and is currently challenging many research laboratories worldwide, in particular for the improved characteristics of these sources such as compactness, versatility and tunability. Among the manifold applications that these sources can enable we can cite their use as injector for large scale accelerators, in medicine, fusion, materials science and cultural heritage. In this lecture I will give a brief overview about the use of laser-plasma sources for applications in material science

Bio: Patrizio Antici studied engineering at Sapienza University of Rome, where he graduated in 1999. After a brief period as consultant in a management consulting firm (Accenture), he obtained a doctorate in physics from Ecole Polytechnique (France) in 2007 in laser-plasma accelerators and a doctorate in engineering from the Sapienza University of Rome (Italy) in electromagnetism/accelerator physics. From 2007 to 2012 he worked at the Italian National Institute for Nuclear Physics (INFN) on laser-driven beamlines, a topic that combines knowledge of lasers and laser-plasma acceleration with that of conventional accelerators. There he has combined scientific activities with more managerial activities within large-scale European projects in the field of lasers and accelerators, in particular the Extreme Light Infrastructure (ELI), in which he was responsible for funding and communication.

In 2012 he integrates the Institut National de la Recherche Scientifique (INRS), where he is currently full professor. His current research interests are focused on the setup and improvement of laser-driven proton and electron beamlines for applications, in particular in the field of material science, cultural heritage, fusion science, and astrophysics. He is a fellow of the European Physical Society, the institute of Physics, and a member of the College of the Royal Society of Canada and alumni of the Global Young Academy.


December 8th, 2022

Exclusive Molecular Images – More Actors, Latest Snapshots

10:30 Vancouver – 11:30 Edmonton – 12:30 Winnipeg – 13:30 Montreal – 14:30 Halifax


Rebecca Boll 

Research Scientist, European XFEL, Hamburg, Germany

X-ray induced Coulomb explosion imaging of complex molecules

Abstract: Recording images of individual molecules with ultrashort “exposure times” has been a long-standing dream in molecular physics, chemistry, and biology, because this would allow one to follow the motion of atoms on their inherent timescale. While X-ray and electron diffraction have been successfully used for larger molecules, both are very challenging to apply to small gas-phase molecules.

We could recently demonstrate that snapshot images of the complete structure of a molecule with eleven atoms, including all hydrogens, can be recorded by Coulomb explosion imaging (CEI) using intense, femtosecond soft X-ray pulses [Nature Physics 18, 423 (2022)]. While it was possible to record up to six-fold ion coincidences in the experiment, even three-fold ion coincidences can be sufficient to image the full structure of a molecule. The X-ray intensity is high enough to produce extreme charge states (e.g. up to 42+ in xenon atoms), and to Coulomb-explode molecules into individual atoms very quickly, such that the initial molecular structure is well preserved in the recorded momenta of all ions. The intriguingly clear momentum images allow us to identify each atom’s position in the molecule unambiguously.

The sensitivity of CEI to the molecular structure at the instant of ionization allows studying processes such as molecular charge-up, the influence of transient molecular resonances, intramolecular charge rearrangement and fragmentation dynamics. The femtosecond pulse duration opens the door to monitoring the temporal evolution of the molecular structure. Furthermore, combining CEI with coincident electron detection provides access to molecular-frame photoelectron diffraction – a powerful tool for accessing molecular dynamics.

Bio: Rebecca Boll is a scientist at the Small Quantum Systems scientific instrument at the European XFEL in Germany since 2017. Her research focuses on ultrafast molecular dynamics and non-linear light/matter interaction in the gas phase, studied with ultrashort and intense X-ray pulses at free-electron lasers. Her particular emphasis lies on (time-resolved) ion momentum spectroscopy using reaction microscopes/COLTRIMS, and velocity-map imaging with time-stamping cameras.

She received the degree of Dr.rer.nat. in physics from Heidelberg University in 2014, under supervision of Prof. Joachim Ullrich and Prof. Daniel Rolles, following a Diplom in physics in 2011, and was a post-doctoral researcher at DESY from 2014 to 2017.

In 2020, she received the FELs of Europe award on FEL science and applications, and has been designated an ‘Emerging Leader’ in the field of Atomic, Molecular and Optical Physics by the Journal of Physics B in 2021.



Yonghao Mi 

JASLAB, University of Ottawa, Ottawa, Canada

A new pathway of H3+ formation

Abstract: We propose and experimentally demonstrate that the trihydrogen cation (H3+) can be produced via single photoionization of the molecular hydrogen dimer (H2-H2). Using near-infrared, femtosecond laser pulses and coincidence momentum imaging, we find that the dominant channel after single ionization of the dimer is the ejection of a hydrogen atom within a few hundred femtoseconds, leaving an H3+ cation behind. The formation mechanism is supported and well reproduced by an ab-initio molecular dynamics simulation. This is a new pathway of H3+ formation from ultracold hydrogen gas that may help explain the unexpectedly high abundance of H3+ in the interstellar medium in the universe.

Bio: Yonghao Mi obtained his Ph.D. in Physics from Heidelberg University. Following Ph.D. training in quantum control of atomic and molecular dynamics with Prof. Thomas Pfeifer at the Max Planck Institute for Nuclear Physics, he received a DFG Postdoctoral Research Fellowship from the German Research Foundation and joined Prof. Paul Corkum’s Joint Attosecond Science Laboratory at the National Research Council of Canada. He is now a Research Associate at the University of Ottawa. His research interests include strong-field physics, attosecond transient absorption spectroscopy, THz generation, and structured light.


November 10th, 2022

How to access ALLS in the future

10:30 Vancouver – 11:30 Edmonton – 12:30 Winnipeg – 13:30 Montreal – 14:30 Halifax


François Légaré

Institut national de la recherche scientifique (INRS), Énergie Matériaux Télécommunications Research Centre (EMT) – ALLS Scientific Director, Varennes, Quebéc, Canada

A new access policy for ALLS to build a diverse user community

Abstract: ALLS has recently been awarded support by the Canada Foundation for Innovation – Major Science Initiatives program. This support allows us to increase the size of the technical team and to significantly reduce the user access fees of 75% of the beamtime in the near future. This beamtime will be allocated to academic and government researchers, which are determined in an external peer-review process. I will discuss details about the changes and chances that are ahead of us.

Bio: François Légaré (Fellow APS, Fellow OPTICA) has been trained as a chemist with a B.Sc. (1998), M.Sc. (2001), and Ph.D. (2004) from the Université de Sherbrooke. During his Ph.D. under the co-supervision of Profs. André D. Bandrauk and Paul B. Corkum, he became an experimentalist with a focus on ultrafast molecular imaging. After a postdoc at Harvard University, he joined INRS-EMT as an assistant professor (2006). He was promoted associate professor in 2010 and full professor in 2013. In 2013, he became the director of the Advanced Laser Light Source. Since the beginning of his career, he has co-authored >180 peer-reviewed publications. More important, he had the opportunity to contribute to the supervision and training of 50 internships, 17 M.Sc and 22 Ph.D. students, and 23 postdoctoral fellows. 



Chandra Breanne Curry 

SLAC National Accelerator Laboratory LaserNetUS Coordinator, Menlo Park, California, USA

LaserNetUS: A network of high-power laser facilities across North America

Abstract: LaserNetUS – a network of 10 high-power laser facilities across North America including the Advanced Laser Light Source (ALLS) at INRS – was established by the U.S. Department of Energy in 2018. LaserNetUS aims to advance the frontiers of ultra‐intense laser‐science as well as their multi- and interdisciplinary applications in various sectors including high energy density, materials, and biomedical science. The mission of LaserNetUS is to advance the frontiers of laser‐science research, provide students and scientists with broad access to unique facilities and enabling technologies, and to foster collaboration among researchers around the world. This talk will provide an overview of the network and how experimental time is awarded through LaserNetUS.

Bio: Chandra Breanne Curry was appointed as the LaserNetUS Coordinator by the U.S. Department of Energy in November 2021. She is based at SLAC National Accelerator Laboratory where she is also a Project Scientist with the Matter in Extreme Conditions Upgrade Project. She is concluding her PhD in the Department of Electrical and Computer Engineering at the University of Alberta and the High Energy Density Science Division at SLAC on petawatt laser-driven ion acceleration.



Scott Feister

California State University Channel Islands – LaserNetUS Review Panel, Venture Country, California, USA

Proposal Writing and Review Process for Mixed-Use Laser Facilities

Abstract: In the past ten years, I have worn many hats in the USA laser community: hands-on graduate student / technician, postdoc in large collaborations traveling for laser beamtime, faculty PI, student mentor, user-community organizer, proposal writer, and proposal reviewer. In this talk, I argue that an effective proposal writing process and proposal review process is one that incorporates all human stakeholder and stakeholder needs. Some examples of stakeholders in the proposal process for a mixed-use, ultrafast laser facility include:

  1. Students and postdocs working at the facility, including their needs for academic recognition, advancing a personal scientific agenda, and career development
  2. Students and postdocs on the proposal team, including their needs for participating in projects with high scientific merit, for hands-on experience with their experiment, orientation at the facility, and human resources while on-site
  3. Staff scientists and administrative coordinators at the facility, including their needs for clear expectations and boundaries for labor beforehand in preparation, and clear expectations on academic recognition
  4. Facility leadership, including their needs that projects advance the prestige and impact of their facility in the scientific community, expand capabilities of their facility, and do-no-harm to their facility
  5. User community members & leaders, including their needs to grow the user community and keep it healthy
  6. Funding agency representatives, including their needs to report ways in which their funded projects have broad impact and high scientific merit
  7. And finally: the proposal-writing PIs, including their needs to succeeding in projects with high scientific merit, to grow collaborations, and to take ownership of their project at all stages

I advocate that this human-centered approach to proposal writing and proposal review process can lead to positive scientific outcomes and a healthy user community.

Bio: Scott Feister specializes in scientific computing: using computers to solve scientific challenges of the 21st century. This specialty is at the intersection of computer science, mathematics, and the natural sciences. In his research, Scott creates data systems and electronic devices for scientific laboratories, performs supercomputer simulations of physical processes, and analyzes large experimental datasets. Scott is a full-time faculty member at California State University Channel Islands (CSUCI). He mentors a variety of undergraduates in research and teaches several computer science courses each semester. As a volunteer, he is the community outreach member of the LaserNetUS i-USE committee.

Scott is currently a PI in collaborative projects on data acquisition and control systems with the Air Force Research Laboratory, Ohio State, and Lawrence Livermore National Laboratory. Prior to becoming a faculty member at CSUCI, Scott completed hands-on experimental graduate work at the Scarlet Laser Facility (Ohio State) and the Extreme Light Facility (Air Force Research Laboratory). Scott also completed two years of postdoctoral work at the Flash Center for Computational Science (University of Chicago), where he contributed to user experiments at the National Ignition Facility and Omega Laser, and two years as an Assistant Researcher at UCLA, participating in laser experiments involving the LAPD (LArge Plasma Device).

September 8th

Good vibrations & excitations: High harmonics and
molecular structures from musical perspective.

10:30 Vancouver – 11:30 Edmonton – 12:30 Winnipeg – 13:30 Montreal – 14:30 Halifax


Michael Spanner 

Theory and Computation Group, National Research Council of Canada, Ottawa, Canada

High-Harmonic Generation is the Sound of the 80’s

Abstract: High-harmonic generations (HHG) is a highly nonlinear optical process where a wide plateau of optical harmonics are generated when intense laser fields interact with atoms, molecules, and solids. The Yamaha DX7 was a revolutionary electronic music synthesizer released in 1983 that quickly dominated the 80s pop music sound. This talk explores the overlap between the strong-field recollision physics leading to HHG and electronic music synthesis as implemented in the DX7

Bio: Michael Spanner received his Ph.D. in Physics from the University of Waterloo. Following a postdoc at the University of Toronto, he is now a Research Officer at the National Research Council, in Ottawa, Canada. He has worked in the areas of strong-field and attosecond science, ionization dynamics, and laser-control of atoms and molecules.



Timothy Cernak

University of Michigan, Ann Arbor, Michigan, USA

Turning Molecules into Music: Chemical Information Transfer via Sonification

Abstract: The information encoded in molecular structures tells us about their bond and atom arrangements, and from this can be inferred additional information about molecular properties such as molecular weight or solubility in water and lipids. Molecules can be drawn as line drawings, but are typically handled in the computer as strings, called SMILES, or matrix arrays of fingerprints. These information media are useful but inherently low dimensional and difficult to interact with and interpret. Music, meanwhile is highly dimensional, easily interpretable to listeners with no background in chemistry, and can be interacted with in many ways. For this reason, encoding molecules as music holds promise as a means to create new drugs, materials, or agrochemicals. We will discuss sonification algorithms developed as a first test of molecule to music information transfer and share early applications in the space

Bio: Tim Cernak was born in Montreal, Canada in 1980. He obtained a B.Sc. in Chemistry from University of British Columbia Okanagan and there studied the aroma profile of Chardonnay wines. Following PhD training in total synthesis with Prof. Jim Gleason at McGill University, Tim was a FQRNT Postdoctoral Fellow with Tristan Lambert at Columbia University. In 2009, Tim joined the Medicinal Chemistry team at Merck Sharp & Dohme in Rahway, New Jersey. There he developed technologies for miniaturized synthesis and late-stage functionalization. In 2013, Tim moved to Merck’s Boston site. In 2018, Dr. Cernak joined the Department of Medicinal Chemistry at the University of Michigan in Ann Arbor as an Assistant Professor. The Cernak Lab is exploring an interface of chemical synthesis and data science. Tim is a co-Founder of Entos, Inc

Seminar July 7th

Caution – Lasers for bio-medical applications

10:30 Vancouver – 11:30 Edmonton – 12:30 Winnipeg – 13:30 Montreal – 14:30 Halifax


Danielle Tokarz 

Saint Mary’s University, Hallifax, Nova Scotia, Canada

Polarization-resolved Second Harmonic Generation Microscopy for Biomedical Applications

Abstract: Information regarding the structure and function of living tissues and cells is instrumental to the advancement of biochemistry and biophysics. Nonlinear optical microscopy, in particular, second harmonic generation (SHG), can provide such information. For instance, SHG microscopy can be used to visualize several biological tissues while polarization-sensitive SHG imaging can be used to extract several parameters related to the ultrastructure of biological tissues. In this talk, I will discuss the use of polarization-resolved SHG microscopy to investigate the ultrastructure of collagen in diseased tissues as well as model systems to understand collagen disorganization in these tissues. I will also discuss the use of polarization-resolved SHG microscopy to investigate other biological tissues including the degradation of otoconia, inner ear calcite crystals which act as linear acceleration sensors.

Bio: Danielle Tokarz obtained her H.B.Sc. degree in 2008 and Ph.D. in 2014 from the University of Toronto where she studied the nonlinear optical properties of conjugated molecules. She completed a postdoctoral fellowship in 2015 at the University Health Network, and undertook an NSERC postdoctoral fellowship at Harvard Medical School, using nonlinear optical microscopy for biomedical applications. In 2017, Danielle started as an assistant professor in the Department of Chemistry at Saint Mary’s University. Her current research program is geared towards characterizing ultrastructural alterations during natural as well as artificial synthesis and degradation reactions in carbohydrate- and protein-dense model systems via development of nonlinear optical microscopy imaging analysis techniques



Simon Vallières

Institut national de la recherche scientifique (INRS), Énergie Matériaux Télécommunications Research Centre (EMT), Varennes, Quebéc, Canada

Tight Focusing in Air of a mJ-class Femtosecond Laser: A Radiation Safety Issue

Abstract: Ultrashort electron beams offer a great potential for applications in areas ranging from material science to radiobiological studies.  We present a very simple method to generate short bunch duration, MeV-ranged electron beams in ambient air through the tight focusing of a mJ-class femtosecond IR laser. Resulting from the copious amounts of electrons generated, the highest measured dose rate of 9 Gy/min at one meter from the source exceeds the annual public dose limit in less than one second of irradiation time, and therefore warrants the implementation of radiation protection.  Laser-plasma interaction simulations confirm the acceleration mechanism and show theoretical agreement with the measured electron energy. Furthermore, we discuss the scalability of the method with the continuing development of mJ-class high average power lasers, moreover providing a promising approach for FLASH radiation therapy.

Bio: Simon Vallières is a postdoctoral researcher at the University of Waterloo in Ontario, and at INRS-EMT in Québec, under the supervision of Prof. Steve MacLean. Simon’s expertise is at the junction of radiation physics and high-intensity laser-matter interactions. Simon obtained a BEng in Engineering Physics at Polytechnique Montreal (2014), then pursued an MSc degree in Medical Physics at McGill University (2016). He completed a dual PhD program at INRS-EMT and Université de Bordeaux in France (2020), during which he worked on laser-based ion acceleration. He now works on the quest for reaching record laser intensities using tight-focusing for probing events in quantum electrodynamics.

Seminar May 12th

Light, heat, and polarization in quantum materials

10:30 Vancouver – 11:30 Edmonton – 12:30 Winnipeg – 13:30 Montreal – 14:30 Halifax


Ziliang Ye 

Physics at Quantum Matter Institute, University of British Columbia, British Columbia, Canada

Ultrafast photovoltaic effect induced by spontaneous polarization in Rhombohedral MoS2

Abstract: Conventional photovoltaic effects result from the drift of optically excited carriers under a built-in electric field, which is induced either by inhomogeneous doping or by interfacing materials of different work functions. On the other hand, a PV effect can also arise in a homogenous single crystalline material with low symmetry in a phenomenon so called bulk photovoltaic effect. Recently we observed a bulk photovoltaic effect in a semiconducting MoS2 with rhombohedral stacking. The effect is enabled by an out-of-plane spontaneous polarization emerging from the unusual stacking order. Compared with conventional PV effects, the 3R MoS2 based device has a similar quantum efficiency with an ultrafast speed and potentially a programmable polarity. Such rhombohedral stacked transition metal dichalcogenides provide a new platform for studying BPV and ferroelectricity at the atomically thin limit.

Bio: Ziliang Ye is an Assistant Professor of Physics at Quantum Matter Institute in the University of British Columbia, where he also holds the Tier II Canada Research Chair. Ziliang’s expertise is in probing two-dimensional materials at ultrafast time scale with subdiffrational length scale using various optical spectroscopy techniques. Ziliang obtained his PhD at the University of California Berkeley in 2013 and worked as a postdoctoral fellow at Columbia and Stanford universities with Tony Heinz before joining the faculty of UBC in 2018. Throughout his career, Ziliang has made several important contributions to the field of quantum materials and nanophotonics and has thus been awarded multiple prizes including MRS gold medalist and the first Kavli Energy NanoScience Institute Thesis Prize Award.



Mengxing (Ketty) Na

Stuart Blusson Quantum Matter Institute, University of British Columbia, British Columbia, Canada

Establishing non-thermal regimes in pump-probe electron-relaxation dynamics

Abstract: Time- and angle-resolved photoemission spectroscopy (TR-ARPES) accesses the electronic structure of solids under optical excitation, and is a powerful technique for studying the coupling between electrons and collective modes. Using TR-ARPES, it has been recently demonstrated that electron-phonon coupling can be extracted from the non-thermal occupation of electrons arising from photoexcitation and subsequent phonon scattering. It is therefore desirable to make a precise estimation of the non-thermal window within which such features arise, and effective temperature models may not be applied. We show that Boltzmann rate equations can be used to calculate the time-dependent electronic occupation function, and reproduce experimental features given by non-thermal electron occupation. Using this model, we define a quantitative measure of non-thermal electron occupation and use it to define distinct phases of electron relaxation in the fluence-delay phase space. More generally, this approach can be used to inform the non-thermal-to-thermal crossover in pump-probe experiments. 

Bio: : MengXing Na is a PhD student and QuEST fellow at the Stuart Blusson Quantum Matter Institute at UBC under the joint supervision of Andrea Damascelli and David Jones. She completed her H.BSc in Physics (2016) at the University of Alberta, where she did research in ultrafast spectroscopy of quantum materials. Currently, she uses time and angle-resolved photoemission spectroscopy to characterize the dynamical electronic structure of quantum materials such as graphene.

Seminar : April 14th

Inspiration, Explanation and sometimes last Hope – Theory

10:30 Vancouver – 11:30 Edmonton – 12:30 Winnipeg – 13:30 Montreal – 14:30 Halifax


André D. Bandrauk 

Département de Chimie, Faculté de Sciences, Université de Sherbrooke, Sherbrooke (Québec), Canada

Circularly Polarized Molecular High Order Harmonics – Generation and Applications in Attosecond Science

Abstract: MHOHG, Molecular high order harmonic generation is a highly nonlinear nonperturbative response of molecules to ultrashort (fs=10-15 s) intense (I>1014 W/cm2) laser pulses leading to multiphoton ionisation and laser induced electron recollisions in linear polarisation. MHOHG is suppressed with intense single circularly polarized pulses but has been shown in 1995 to be generated with co- or counter-rotating pairs of bichromatic  (ω1/ω2=n1/n2) circularly polarised pulses [1-2] leading to the generation of circularly polarised attosecond (10-18 s) pulses [3], the time scale of electron motion in atoms and molecules. Parallel computer simulations of electron TDSE,s, Time Dependent Schrödinger Equations coupled with photon Maxwell,s equations  show that molecules are the ideal systems for circular polarised harmonic and attosecond pulse generation due to lower rotational symmetries than atoms. The TDSE simulations confirm the electron-parent ion recollision mechanism in the presence of bichromatic circular pulses and maximum circular polarised MHOHG efficiency is obtained when the net time dependent electric field of the combined pulses is compatible with molecular symmetry. The resulting circularly polarised attosecond pulses are shown to generate in molecules coherent attosecond quantum electron currents from which one can create intense attosecond magnetic field pulses for studying ultrafast  magneto-optics [4] and dynamical symmetry  in molecules [5].

[1] T Zuo, A D Bandrauk, J Nonlinear Opt Phys Mater 04, 533 (1995) 

[2] S Long, W Becker, J K McIver, Phys Rev A 52, 2262 (1995) 

[3] K J Yuan, A D Bandrauk, Phys Rev Lett 110, 023003 (2013) 

[4] A D Bandrauk, J Guo, K J Yuan, J Opt 19, 124016 (2017) 

[5] K J Yuan, A D Bandrauk, Phys Rev A 97, 023408 (2018)

Bio: B.Sc. (Hon. Chem.) from l’Université de Montréal, M.Sc. in theoretical chemistry from M.I.T. and Ph.D. in Chemical Physics from McMaster University (Hamilton, Canada), NATO Fellow at Oxford University’s Mathematical Institute (1968-70), assistant at the Technische Hochschule Munchen (1970) before being appointed as an assistant professor of theoretical chemistry at l’Université de Sherbrooke. He has been an invited researcher and lecturer at prestigious institutions:  International Collaborator, Los Alamos Natl. Lab., USA (1984); Senior Visiting Scientist, NRC-Ottawa (1985); Foreign Lecturer, Institute of Chem. Phys., Moscow, USSR (1985); C.A. McDowell Lecturer, University of British Columbia, Vancouver (1990); Foreign Professor, Institute for Molecular Science, Okazaki, Japan (1992);  Japan Society for Promotion of Science Lecturer, (Tohoku Univ.-1997); Visiting Professor, Université de Paris Sud (Orsay), (1998);  Invited speaker, Harvard University (2008, 2005, 2002, 1995, 1993), M.I.T. (2000, 2018).  In 1982, awarded a Killam Research Fellowship by the Canada Council, was elected as a Fellow to the Royal Society of Canada in 1992.  In 1989 received the Herzberg prize from the Canadian Spectroscopy Society, awarded the prestigious John Polanyi (Nobel Prize 1986) Awardby the Chemical Society of Canada in 2001, became director of the Center for parallel computing and IBM Center of Excellence at l’Université de Sherbrooke and is member of the new National Center of Excellence in Photonics. He is appointed a Canada Research Chairin Computational Chemistry & Molecular Photonics from 2002 to 2016 and a new Fellow of the American Association for the Advancement of Science, AAAS (2003). He became Chair of the Department of Chemistry in 2005 and in 2007 received a Prize from the Humboldt Foundation (Berlin, Germany). He was awarded the NSERC – J. C. Polanyi Prize for Attosecond Science (with P. B. Corkum, NRC) in 2008. He has also been elected Fellow of the American Physical Society (FAPS).  In 2009 he is elected Fellow of SIAM (Society for Industrial and Applied Mathematics, USA).  The 8th International Symposium on Ultrafast Intense Laser Science (ISUILS8) was held in his honour in 2009.  In 2010 he receives the Prix du Québec.  The Governor General of Canada appoints him in 2012 as an Officer of the Order of Canada for pioneering work in Attosecond Chemistry.  The MUST (Molecular Ultrafast Science Technology) program of ETH-Zurich has invited him to deliver the FAST (Femto-AttoSecond Science-Technology) Fellow lectures in 2014. The Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences nominates A.D. Bandrauk to the Wang T.C. Lecture Professorship in 2017.



Simon Neville

Research Computing Specialist at the National Research Council Canada, Ottawa, Canada

Using electronic coherences to probe excited state molecular dynamics: a user guide

Abstract: Understanding the fate of molecules following photo-excitation is of central importance in many areas, including studies of vision, photosynthesis, and light harvesting systems. Ultrafast electronic relaxation driven by strong non-adiabatic interactions of the nuclear and electronic degrees of freedom are key to understanding these processes, and constitutes an area of intense and continued study. 

Experimentally, such ultrafast internal conversion processes can be probed using femtosecond pump-probe spectroscopies. The choice of probe here is key to being able to disentangle the vibronic dynamics initiated by the pump pulse. Traditionally, spectroscopic probes sensitive to electronic state populationshave enjoyed great success. Recently, however, there has been great interest in using probes which are instead sensitive to the electronic coherencesthat may form as a result of non-adiabatic coupling of the initially excited state to its complement. The aim of this talk is to explore whether electronic coherences are a general descriptor of excited state dynamics, and to highlight the situations in which they are likely to be of use.

Using simple symmetry arguments, we show that large amplitude electronic coherences are, in fact, not guaranteed to form during the course of excited state dynamics. In particular, this will occur when the electronic states involved possess different point group symmetries at the Franck-Condon point. Furthermore, we explore the role of conical intersection topography and the nuclear coordinate dependence of transition dipole moments, with both being found to play important roles in governing the magnitude of the coherence that can form.

The upshot of these results is that spectroscopies sensitive to electronic coherences are not general probes of excited state molecular dynamics, and will only be of use for a subset of systems, which may be identified using a simple set of rules. 

Bio: Simon Neville is a Research Computing Specialist at the National Research Council Canada, Ottawa, with an interest in the theory and simulation of non-adiabatic excited-state dynamics and ultrafast pump-probe spectroscopies. Prior to this appointment, he was a postdoctoral research fellow at the University of Ottawa working in the groups of Michael Schuurman and Albert Stolow, and obtained his PhD in the group of Graham Worth at the University of Birmingham.