Events

From Hollow-Core Nonlinear Optics to High-Field Physics

Professor François Légaré Full Professor Director of the Energy Materials and Telecommunications Centre at INRS

Presented in person in Wilmot 116 and on Zoom

 Abstract

Since the pioneering work of Nisoli and co-workers on generation of few-cycle laser pulses with hollow-core fiber (HCF) compression, HC waveguide technologies have established themselves as unique platforms for pulse compression and frequency conversion spanning the UV to the mid-IR spectral range. Until recently, multimodal nonlinear optical propagation in the HCF was assumed to be detrimental for pulse compression, and peak power at the HCF output was limited to ~0.5 TW.

In this talk, I will present experiments, supported by numerical simulations, showing how controlled multimode nonlinear propagation can overcome these limitations. First, I will discuss Raman-driven multidimensional solitary states in molecular-gas-filled HCFs, which provide a route toward longer-wavelength, red-shifted pulses with intrinsic negative chirp and compression from sub-picosecond duration to below 25 fs using normal material dispersion. I will then show recent results in short HCFs where spatiotemporal dynamics enable efficient UV-visible generation. Finally, I will discuss peak-power scaling and applications of the HCF technology for high-field physics, including electron acceleration under tight focusing and high-dose-rate MeV electron beam generation in ambient air. Future perspectives will also be discussed.

Biography

Professor François Légaré is a chemical physicist who specializes in developing novel approaches for ultrafast science and technologies, as well as biomedical imaging with nonlinear optics. He joined the Energy Materials Telecommunications Center of INRS in 2006 and became full professor in 2013. From 2013 to 2023, he was the director of the Advanced Laser Light Source. Under his leadership, ALLS was upgraded with high average power Ytterbium laser systems and advanced instrumentation for time-resolved material characterization, has joined the LaserNetUS network, and the facility is recognized as a national infrastructure by the Canada Foundation for Innovation. He is the vice-chair of LaserNetUS (2024-2026). Through his research, he is fostering the transfer of technologies to Canadian spin-off companies, including few-cycle Inc. and MD Photonique Inc. He was awarded the Herzberg medal from the Canadian Association of Physics in 2015, and the Rutherford Memorial Medal in physics of the Royal Society of Canada in 2016. Professor Légaré is a fellow of the American Physical Society and of Optica.