Cheng Li, University of Ottawa

Leuchs-Russell-Auditorium, A.1.500, Staudtstr. 2

Location details

Abstract:
Entangled photon pairs generated from spontaneous parametric down-conversion (SPDC) are widely implemented in many quantum technologies. In each degree of freedom (DoF)—such as polarization, spatial mode, or time—the maximally attainable entanglement through SPDC is upper-bounded by the coherence of the beam that pumps SPDC. However, such a constraint may not hold when the desired entanglement is in a different DoF from that of the pump beam. In particular, the spatiotemporal properties of the pump do not directly influence the degree of polarization entanglement but instead imprint structures derived from realistic experimental conditions. This talk outlines the influence of such cross-DoF structures in entanglement generation and shows that they can either be (i) flattened so that maximum polarization entanglement can be produced from light sources with arbitrary spatiotemporal properties, or (ii) leveraged to generate novel entangled states. These perspectives show that cross-DoF effects are not limitations but resources, offering new pathways to engineer robust, high-dimensional entanglement for applications in quantum communication, computation, and sensing.