Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 14: Poster II

HL 14.1: Poster

Monday, March 18, 2024, 15:00–18:00, Poster F

Restoral of the Single-Photon Purity at a 2π Excitation of a Quantum Two-Level System — •Patricia Kallert¹, Lukas Hanschke¹, Melina Peter², Ailton José Garcia Junior², Eva Schöll¹, Saimon Filipe Covre Da Silva², Santanu Manna², Armando Rastelli², and Klaus D. Jöns¹ — ¹PhoQS Institute, CeOPP, and Department of Physics, Paderborn University, Paderborn, Germany — ²Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Linz, Austria

Exploring the properties of single-photons and their generation from for instance semiconductor quantum dots is critical to developing photonic quantum technologies. The coupling of resonant, coherent laser pulses to a quantum two-level system leads to Rabi rotations between the ground and excited state. In a dephasing-free system, a 2π rotation then leads to either (i) two population inversions and therefore no photon emission or (ii) the emission of two successive photons, if after an emission during the presence of the pulse the system is re-excited.[1] Due to the different temporal shapes, the consecutive photons exhibit different spectral bandwidths, as related by the Fourier transform limit. Here we verify this prediction of different bandwidths for both photons using narrow filtering. By filtering the spectrally broad first photon, we*re reducing the probability of detecting two photons from the same excitation pulse. Our study should help to identify the optimal excitation conditions for applications in quantum technologies.

Keywords: Two-Level Systems; Single-Photon Sources; Quantum Dots