Parts | Days | Selection | Search | Updates | Downloads | Help

Q: Fachverband Quantenoptik und Photonik

Q 20: QuanTour II – Multi-photon Effects & Entanglement

Q 20.1: Invited Talk

Tuesday, March 3, 2026, 11:00–11:30, P 7

Entangled photons from GaAs quantum dots in tunable circular Bragg resonators — •Armando Rastelli — Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Linz, Austria

Entanglement is one of the most fascinating phenomena in quantum physics and a key resource for quantum technologies. Different from probabilistic sources, Quantum Dots (QDs) can emit polarization entangled photon pairs with negligible probability of multi-pair emission using the biexciton-exciton radiative cascade.

To make such sources practical, it is important to maximize the degree of entanglement, brightness, maximum emission rate, photon indistinguishably, and to be able to fine-tune the wavelength of the emitted photons. Ideally, the source should fulfill these requirements even when operated at temperatures of 30-40 K, that are reachable with compact cryocoolers. Meeting this list of requirements on a single QD device is a formidable challenge.

In this presentation, we will present our contribution to the field by focusing on GaAs QDs embedded in strain- and electrically-tunable circular Bragg resonators (CBRs). By making use of the intrinsically short lifetimes of GaAs QDs, the Purcell enhancement in the CBRs, as well as coherent excitation schemes, we will discuss the feasiblity of practical and scalable sources of entangled photons based on QDs.

Keywords: Quantum Dots; Entangled Photons; Circular Bragg resonators; Strain tuning