Quantum dot single-photon emission coupled into single-mode fibers with 3D printed micro-objectives
Lucas Bremer,
Ksenia Weber,
Sarah Fischbach,
Simon Thiele,
Marco Schmidt,
Arsenty Kaganskiy,
Sven Rodt,
Alois Herkommer,
Marc Sartison,
Simone Luca Portalupi,
Peter Michler,
Harald Giessen,
Stephan Reitzenstein
Affiliations
Lucas Bremer
Institute of Solid State Physics, Technische Universität Berlin, Berlin, Germany
Ksenia Weber
4th Physics Institute and Research Center SCoPE and Integrated Quantum Science and Technology Center IQST, University of Stuttgart, Stuttgart, Germany
Sarah Fischbach
Institute of Solid State Physics, Technische Universität Berlin, Berlin, Germany
Simon Thiele
Institute for Applied Optics (ITO) and Research Center SCoPE, University of Stuttgart, Stuttgart, Germany
Marco Schmidt
Institute of Solid State Physics, Technische Universität Berlin, Berlin, Germany
Arsenty Kaganskiy
Institute of Solid State Physics, Technische Universität Berlin, Berlin, Germany
Sven Rodt
Institute of Solid State Physics, Technische Universität Berlin, Berlin, Germany
Alois Herkommer
Institute for Applied Optics (ITO) and Research Center SCoPE, University of Stuttgart, Stuttgart, Germany
Marc Sartison
Institut für Halbleiteroptik und Funktionelle Grenzflächen, Center for Integrated Quantum Science and Technology (IQST) and Research Center SCoPE, University of Stuttgart, Stuttgart, Germany
Simone Luca Portalupi
Institut für Halbleiteroptik und Funktionelle Grenzflächen, Center for Integrated Quantum Science and Technology (IQST) and Research Center SCoPE, University of Stuttgart, Stuttgart, Germany
Peter Michler
Institut für Halbleiteroptik und Funktionelle Grenzflächen, Center for Integrated Quantum Science and Technology (IQST) and Research Center SCoPE, University of Stuttgart, Stuttgart, Germany
Harald Giessen
4th Physics Institute and Research Center SCoPE and Integrated Quantum Science and Technology Center IQST, University of Stuttgart, Stuttgart, Germany
Stephan Reitzenstein
Institute of Solid State Physics, Technische Universität Berlin, Berlin, Germany
User-friendly single-photon sources with high photon-extraction efficiency are crucial building blocks for photonic quantum applications. For many of these applications, such as long-distance quantum key distribution, the use of single-mode optical fibers is mandatory, which leads to stringent requirements regarding the device design and fabrication. We report on the on-chip integration of a quantum dot (QD) microlens with a 3D-printed micro-objective in combination with a single-mode on-chip fiber coupler. The practical quantum device is realized by the deterministic fabrication of the QD-microlens via in situ electron-beam lithography and the 3D two-photon laser writing of the on-chip micro-objective and fiber chuck. A QD with a microlens is an efficient single-photon source, whose emission is collimated by the on-chip micro-objective. A second polymer microlens is located at the end facet of the single-mode fiber and ensures that the collimated light is efficiently coupled into the fiber core. For this purpose, the fiber is placed in an on-chip fiber chuck, which is precisely aligned to the QD-microlens thanks to the sub-micrometer processing accuracy of high-resolution two-photon direct laser writing. The resulting quantum device has a broadband photon extraction efficiency, a single-mode fiber-coupling efficiency of 22%, a measured single-photon flux of 42 kHz (8.9 kHz) under cw (pulsed) optical excitation, which corresponds to 1.5 MHz (0.3 MHz) at the single-mode fiber output, and a multi-photon probability in terms of g(2)(0) = 0.00±0.000.04 (0.13 ± 0.05) under cw (pulsed) optical excitation. The stable design of the developed fiber-coupled quantum device makes it highly attractive for integration into user-friendly plug-and-play quantum applications.
