Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 25: Poster 1

HL 25.56: Poster

Mittwoch, 7. September 2022, 18:00–20:00, P2

Efficient spectral separation of single and entangled photons — •Patricia Kallert, Lukas Hanschke, Eva Schöll, Björn Jonas, and Klaus D. Jöns — Institute for Photonic Quantum Systems, Center for Optoelectronics and Photonics Paderborn, and Department of Physics, Paderborn University, 33098 Paderborn, Germany

Experiments and protocols based on single-photons with different properties are crucial to develop photonic quantum technologies. Semiconductor quantum dots are a promising platform for the emission of single, indistinguishable, and entangled photons. The efficient routing and filtering of frequency-mismatched photons, for example, from the biexciton-exciton cascade, is crucial to facilitate the full potential of quantum dots. The separation of photons of different energies allows for efficient entanglement swapping and teleportation experiments, which rely on multiphoton coincidences. Spectral separation and simultaneous detection of adjacent wavelengths are complex to realise. Here we exploit a strategy to build a blaze grating-based transmission spectrometer with outstanding figures of merit. We shed light on the basic principle and the pitfalls that lead to a severe decrease of the efficiency or deterioration of the resolution and how to overcome them. Balancing the main properties, our overall efficiency exceeds 66 %, and our resolution is 21 GHz. Simultaneously, wavelengths distanced by 0.2 nm can be separated. Our self-built setup offers all functionalities to characterise single-photon sources and efficiently incorporate them in modern quantum optics experiments.