Ultrafast terahertz spectroscopy of quantum materials

Our eyes are amazing detectors. They can distinguish between many colors, patterns and textures to help us identify the finest details and properties of objects surrounding us. It might then seem surprising to discover that some of the materials with the most exotic properties, such as semiconductors, semi-metals and superconductors, have a rather “boring” visual appearance. In fact, these materials would be extremely “colorful” if we were able to resolve light beyond the visible region. In the mid- and far-infrared regions of the electromagnetic spectrum, they display many optical signature resonances attesting of a wild range of microscopic interactions. In our labs, we develop new ultrafast optical sources in the infrared region and we use them to resolve microscopic dynamics in these condensed matter systems. Our optical sources produce broadband phase-locked infrared pulses, also called terahertz (THz) pulses in reference to the light’s oscillation frequency, which we use to perform ultrafast spectroscopy. We recently started exploring macroscopic quantum states in semiconductor microcavities. These samples contain exciton-polaritons, which are quasi-particles with a dual light-matter nature providing them with unique properties. At low temperatures, exciton-polaritons collectively reach a coherent quantum state in a process reminiscent of Bose-Einstein condensation. Our goal is to better understand this new state of matter and develop optical techniques to control it. This quantum state has a great potential to become one of the main building blocks for future quantum computation or quantum communication technologies.

Jean-Michel Ménard is a researcher in the field of ultrafast terahertz spectroscopy. He completed his PhD in 2010 under the guidance of Prof. van Driel at the University of Toronto. He was then awarded a Humboldt Fellowship to research ultrafast phenomena in cavity quantum electrodynamics in the laboratory of Prof. Huber at the University of Regensburg. In 2014, he joined the Russell Division at the Max Planck Institute for the Science of light in Erlangen as a postdoctoral researcher to work on nonlinear optical effects in photonic crystal fibers. He joined the University of Ottawa in 2016 as an assistant professor where he now conducts multidisciplinary experiments in the fields of optics, photonics and condensed matter. His research interests include time-resolved terahertz spectroscopy of quantum materials and the development of photonics tools based on nonlinear optical propagation in gas-filled hollow-core fibers.