Biography
Duncan England obtained a BSc. and MSc. in Physics and Astronomy from the University of Durham in 2006, and a D.Phil in Atomic and Laser Physics from the University of Oxford in 2011. In 2012, he arrived at the National Research Council for a 2-year postdoc and liked it so much that he never left. An over-arching theme in his research at NRC is the idea that intense ultrafast pulses of light can be used to generate and manipulate the faintest pulses possible – single photons. He can think of few, if any, places in the world better to pursue this research than Ottawa which is home to world-leading scientists and laboratories in both ultrafast laser science and quantum optics.
Abstract
I will discuss the development of an ultrafast all‑optical Kerr switch that allows the manipulation and gating of single photons on picosecond timescales. In the context of quantum information, this capability enables ultrafast time‑bin encoding, where the separation between bins is measured in picoseconds rather than nanoseconds. In this regime, bulky interferometers can be replaced by birefringent crystals, and interferometric stability lasts days rather than seconds.
Our group has explored several applications of this approach, including quantum frequency conversion, quantum random walks, and rudimentary quantum processing. I will briefly introduce these topics before focusing on our demonstrations of laboratory‑scale ultrafast quantum communication. In its simplest form, the switch can function as a near single‑mode filter for pulsed light, and we show quantum communication in the presence of 10^9 noise photons per second. I will also show how the switch can reversibly map between time‑bin and polarization encodings, enabling quantum key distribution with qubits, and discuss how this method can be extended to higher‑dimensional qudits.