Archives: Presenters

Optically Generated Magnetic Fields

based on a joint work of

1. B. Corkum¹, K. Jana¹, S. Möller¹, Y. Mi¹, S. Sederberg¹, M. Mountney² and A. Emmouilidou²

¹Joint Attosecond Science Laboratory, University of Ottawa, and National Research Council of Canada

²University College London

Summary:  Isolated magnetic fields are used extensively in solid state physics, medical physics, and chemistry.  These magnetic fields are often generated in wire loops with Biot-Savart law relating the time-dependent current flowing to a dynamic magnetic field.  However, physical wires constrain the magnitude, the time-dependence, and the dimensions of the fields.

Controlled currents can be optically injected into semiconductors, dielectrics, gases, or plasmas using coherent control – the perturbative or non-perturbative interference of quantum pathways from an initial state to a final state in the material itself.  Like their wire counterparts, these material currents create fields, but with different constraints than those generated by physical wires.

Optical injection allows the spatial dimensions to be confined to the focal volume of a vacuum ultraviolet (VUV) pulse (~100 nm) while the rise time of the current is determined by the femtosecond pulse duration of the exciting beams.  Furthermore, since the magnitude and direction of these currents are controlled by interference, the motion of the charge carriers can be controlled with a spatial-light modulator.  I will describe how we measure current in GaAs and the dynamic near-field magnetic structure that Maxwell’s equations imply.  I will also describe the space-time coupled field that is radiated (sometimes called a “flying doughnut”) and measured by electro-optic sampling.  I will conclude with a space-time measurement of the linear electronic spectrum of water vapor in the THz spectral region.

BIO: Dr. Paul Corkum

Paul Corkum graduated from Lehigh University, USA, with a Ph. D. in theoretical physics in 1972. In 1973, he joined the staff of the National Research Council (NRC) of Canada where he built one of the world’s most famous groups working on the interaction of very short light pulses with matter. Dr. Corkum is a Full Professor of Physics and a Canada Research Chair at the University of Ottawa, and directs the Joint NRC/University of Ottawa Attosecond Science Laboratory. He is a member of the Royal Society of London and of the Royal Society of Canada, and also a foreign member of the US National Academy of Science, the Austrian Academy of Science, and the Russian Academy of Sciences. Among his many honours and recognitions, he has received the 2017 Royal Medal for his major contributions to laser physics and the development of the field of attosecond science, as well as the Schneider Medal, the highest NRC distinction bestowed upon NRC researchers. In 2018, Dr. Corkum was awarded both the SPIE Gold Medal, and the Isaac Newton Medal and Prize from the UK Institute of Physics. In 2019, he received the Willis E. Lamb Award for Laser Science and Quantum Optics. Most recently, the Wolf Foundation selected Dr. Corkum as the recipient of the 2022 Wolf Prize Laureate in Physics.

SI Second and UTC – Today and Tomorrow

The second still remains the best realised unit in SI (it has the smallest uncertainties), but this is no longer enough for frequency and time (F&T) metrologists and they are preparing for the redefinition of the second in the next few years. International F&T community is working hard nowadays to prepare all stakeholders for the new optical second that will have the realisation uncertainties at 1E-18 level, compared to 1E-16 level of the microwave Caesium standards.

In addition to new frequency standards, the attention to the accessibility and stability of UTC is high priority; modern technologies require high accuracy and secure time synchronization and F&T metrology is developing systems and methods that allow the transition of nanosecond accuracy from the National Labs to the client’s systems.

I will present NRC F&T work that covers a wide range of activities – Caesium fountain NRC primary frequency standard realizing the SI second for Canada, portable single trapped Strontium Ion optical clock that will provide NRC with access to new optical SI second, and nanosecond accuracy time dissemination for the most demanding applications.

BIO: Dr. Marina Gertsvolf

Dr. Marina Gertsvolf is the Team Leader for Frequency and Time (F&T) group at National Research Council (NRC) Canada and is responsible for realising the second, an SI unit of time, and for maintaining and disseminating the official time for Canada, UTC(NRC).

Dr. Gertsvolf received her PhD from the University of Ottawa in 2009 and joined NRC as a research officer the same year. In 2016 she became the F&T team leader and has been leading the group and the development of the next generation frequency standards and dissemination services that meet and exceed current industry and society needs. NRC F&T group operates and develops among other, the caesium fountain atomic clock, the primary realisation of SI second; the single trapped strontium ion clock, the most accurate frequency standard in Canada and one of the best in the world; the nanosecond accuracy time dissemination service to remote clients in support of the critical infrastructure needs, and the frequency comb systems for frequency calibration and comparisons.

Dr. Gertsvolf serves on several international committees and working groups. Among others she is the Commission A Chair of Canadian National Committee for the International Union of Radio Science (URSI), the Chair of the International Atomic Time Working Group at the Consultative Committee of Time and Frequency (CCTF-WGTAI) and the Deputy Technical Chair of the Systema Interamericano de Metrologia (SIM).

Sponsored by Keithley Instruments, a Tektronix Co., and the IEEE Instrumentation and Measurement Society

IAN HUNTER

For the development and commercialization of nonlinear system identification techniques in instrumentation and measurement applications

Having spent much of his childhood designing and building various machines and measurement instruments in a home electronics shop and chemistry laboratory, Ian Hunter’s passion is the creation of new instruments and measurement techniques at the micro scale that benefit society. He and his students have developed many novel instruments and devices including confocal laser microscopes, scanning tunneling electron microscopes, miniature mass spectrometers, new forms of Raman spectroscopy, needle-free drug delivery technologies, microsurgical robots, robotic endoscopes, high-performance Lorentz-force motors, and microarray technologies for massively parallel chemical and biological measurements. He has founded or cofounded over 30 companies, many of which feature technologies incorporating the novel use of nonlinear system identification techniques both in conducting measurements and in the control of their instrumentation systems.

An IEEE Life Member, Hunter is the Hatsopoulos Professor in Thermodynamics at the Massachusetts Institute of Technology, Cambridge, MA, USA.