19 March 2026

Title: Strong-Field Quantum Optics: Probing Relativistic Interactions with Non-Classical Light

Speaker: Dr. Kenan Qu, Department of Astrophysical Sciences, Princeton University

Abstract of Talk : Strong-field physics and quantum optics have historically occupied opposite ends of the energy spectrum. In this colloquium, we bridge this gap by asking how non-classical light statistics influence interactions in the extreme relativistic limit.

We begin with an overview of "strong-field quantum optics," distinguishing this regime by the onset of field-induced relativity. Unlike traditional quantum optics which probes bound states, this regime is characterized by free electrons driven to relativistic velocities within a single optical cycle, where quantum recoil becomes a dominant factor.

Against this backdrop, we explore three interconnected frontiers. First, we show that a non-classical drive imprints distinct signatures on nonlinear Compton scattering spectra, differing from coherent laser drivers due to the underlying photon statistics. Second, we explore vacuum engineering, demonstrating that a squeezed vacuum environment can effectively tune relativistic emission rates. Finally, we propose using plasmas as nonlinear media to generate the required intense quantum states via parametric four-wave mixing or plasma waves. These topics provide a unified perspective on harnessing non-classicality in the relativistic domain.

Profile of Speaker: Kenan Qu is a Research Scholar in the Department of Astrophysical Sciences at Princeton University. He received his Ph.D. in Physics from Oklahoma State University in 2015. Dr. Qu’s research explores the intersection of plasma physics and quantum optics, with a broad focus on plasma quantum optics, nonlinear plasma photonics, and strong-field QED. His recent work investigates "strong-field quantum optics," probing how non-classical light statistics and vacuum engineering influence interactions in the extreme relativistic limit, alongside methods to generate ultrabright quantum states using plasmas. He serves as a Program Committee Member for the SPIE Optics+Optoelectronics conference.