TY - JOUR

T1 - Experimental optimization of the fiber coupling efficiency of GaAs quantum dot-based photon sources

AU - Nie, Weijie

AU - Sharma, Nand Lal

AU - Weigelt, Carmen

AU - Keil, Robert

AU - Yang, Jingzhong

AU - Ding, Fei

AU - Hopfmann, Caspar

AU - Schmidt, Oliver G.

N1 - Funding Information: The authors thank Michael Zopf of Leibniz Universität Hannover for fruitful discussions and suggestions. This work was financially supported by the BMBF project Q.link.X under Grant Agreement No. 100362122 and the European Research Council Horizon 2020 project QD-NOMS under Grant Agreement No. 715770.

PY - 2021/12/14

Y1 - 2021/12/14

N2 - We present an efficient experimental method to optimize the combined extraction efficiencies and the far-field emission patterns of solid state-based single and entangled photon pair sources for efficient coupling to single mode fibers. This method is demonstrated for emitters based on droplet etched GaAs quantum dot nanomembranes attached to gallium phosphide solid immersion lenses using an adhesive layer of poly(methyl methacrylate). By varying the thickness of the latter, the optimization of both the extraction efficiency and the far-field emission pattern for single mode fiber coupling is facilitated. The applied method of far-field characterization is validated by benchmarking it against direct measurements of the single mode fiber coupling efficiency. Using this scheme, devices with a more than 150-fold enhanced free-space intensity compared to an unprocessed sample as well as a fiber coupling efficiency of 64% are achieved. In addition, the optimized device has been employed for on-demand generation of maximally entanglement photon pairs using two-photon excitation of the quantum dot bi-exciton exciton cascade. This universal approach for experimental optimization can be applied to other photonic nanostructures, including circular Bragg grating and micropillar cavities as well as monolithic microlenses.

AB - We present an efficient experimental method to optimize the combined extraction efficiencies and the far-field emission patterns of solid state-based single and entangled photon pair sources for efficient coupling to single mode fibers. This method is demonstrated for emitters based on droplet etched GaAs quantum dot nanomembranes attached to gallium phosphide solid immersion lenses using an adhesive layer of poly(methyl methacrylate). By varying the thickness of the latter, the optimization of both the extraction efficiency and the far-field emission pattern for single mode fiber coupling is facilitated. The applied method of far-field characterization is validated by benchmarking it against direct measurements of the single mode fiber coupling efficiency. Using this scheme, devices with a more than 150-fold enhanced free-space intensity compared to an unprocessed sample as well as a fiber coupling efficiency of 64% are achieved. In addition, the optimized device has been employed for on-demand generation of maximally entanglement photon pairs using two-photon excitation of the quantum dot bi-exciton exciton cascade. This universal approach for experimental optimization can be applied to other photonic nanostructures, including circular Bragg grating and micropillar cavities as well as monolithic microlenses.

UR - http://www.scopus.com/inward/record.url?scp=85121567837&partnerID=8YFLogxK

U2 - 10.1063/5.0059310

DO - 10.1063/5.0059310

M3 - Article

AN - SCOPUS:85121567837

VL - 119

JO - Applied physics letters

JF - Applied physics letters

SN - 0003-6951

IS - 24

M1 - 0059310

ER -