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HL: Fachverband Halbleiterphysik

HL 24: Quantum dots: Optics

HL 24.6: Talk

Wednesday, March 29, 2023, 10:45–11:00, POT 151

Generation of indistinguishable and entangled photons at telecom frequencies using tailored cavity designs — •David Bauch, Dustin Siebert, Jens Förstner, Klaus D. Jöns, and Stefan Schumacher — Department of Physics, Electrical Engineering and CeOPP, Paderborn University, Germany

The commonly utilized biexciton-exciton cascade yields photons with intrinsically limited indistinguishability [1]. By tuning the biexciton-exciton lifetime ratio, large increases in single photon indistinguishability can be achieved [1,2]. Using the cavity-induced Purcell enhancement is a simple method for radiative lifetime tuning. Employing a circular Bragg reflector at telecom wavelengths for suitable quantum dots allows for a Purcell enhanced biexciton-exciton transition, while still maintaining high extraction efficiency for the exciton-ground state transition. The decreased lifetime of the biexciton results in a faster emission of then indistinguishable single photons. Here, we demonstrate this effect numerically and determine the theoretically required parameters for the biexciton-exciton transition to yield highly indistinguishable single photons, which are also entangled with their exciton-ground state emission counterpart. We guide our calculations using Maxwell simulations for the cavity design, allowing for close-to real-life system predictions. Our simulation demonstrates the robust increase of the indistinguishability of the emitted photons even when accounting for electron-phonon coupling at low temperatures.

[1] E. Schöll, et al., Physical Review Letters 125, 233605 (2020) [2] F. Sbresny, et al., Physical Review Letters 128, 093603 (2022)