Bright Single-Photon Sources Based on Anti-Reflection Coated Deterministic Quantum Dot Microlenses

Technologies

Peter Schnauber³  Alexander Thoma³  Christoph V. Heine³  Alexander Schlehahn³  Liron Gantz²  Manuel Gschrey³  Ronny Schmidt³  Caspar Hopfmann³  Benjamin Wohlfeil⁴  Jan-Hindrick Schulze³  André Strittmatter³  Tobias Heindel³  Sven Rodt³  Ulrike Woggon¹  David Gershoni²  Stephan Reitzenstein³ 

[1] Institut für Optik und Atomare Physik, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany;The Physics Department, Technion—Israel Institute of Technology, Haifa 32000, Israel;Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany;Zuse-Institut Berlin (ZIB), Takustraße 7, 14195 Berlin, Germany;

关键词: quantum dots;    deterministic devices;    quantum optics;    single-photon source;    anti-reflection coating;    extraction efficiency;   

DOI  :  10.3390/technologies4010001

来源: mdpi

【 摘 要 】

We report on enhancing the photon-extraction efficiency (PEE) of deterministic quantum dot (QD) microlenses via anti-reflection (AR) coating. The AR-coating deposited on top of the curved microlens surface is composed of a thin layer of Ta₂O₅, and is found to effectively reduce back-reflection of light at the semiconductor-vacuum interface. A statistical analysis of spectroscopic data reveals, that the AR-coating improves the light out-coupling of respective microlenses by a factor of 1.57 ± 0.71, in quantitative agreement with numerical calculations. Taking the enhancement factor into account, we predict improved out-coupling of light with a PEE of up to 50%. The quantum nature of emission from QDs integrated into AR-coated microlenses is demonstrated via photon auto-correlation measurements revealing strong suppression of two-photon emission events with g⁽²⁾(0) = 0.05 ± 0.02. As such, these bright non-classical light sources are highly attractive with respect to applications in the field of quantum cryptography.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.