Enhancing the photon-extraction efficiency of site-controlled quantum dots by deterministically fabricated microlenses

Abstract

We report on the realization of scalable single-photon sources (SPSs) based on single site-controlled quantum dots (SCQDs) and deterministically fabricated microlenses. The fabrication process comprises the buried-stressor growth technique complemented with low-temperature in-situ electron-beam lithography for the integration of SCQDs into microlens structures with high yield and high alignment accuracy. The microlens-approach leads to a broadband enhancement of the photon-extraction efficiency of up to (21 ± 2) % and a high suppression of multi-photon events with g (2) (τ = 0) < 0.06 without background subtraction. The demonstrated combination of site-controlled growth of QDs and insitu electron-beam lithography is relevant for arrays of efficient SPSs which can be applied in photonic quantum circuits and advanced quantum computation schemes.

Ultra-long-working-distance spectroscopy of single nanostructures with aspherical solid immersion microlenses

“…Efficient light delivery to and collection from microoptical systems, in particular light emitters, is of paramount importance for their application potential and performance. It has been approached in many different ways: by placing mirrors beneath the light emitters, coating the substrate surface with anti-reflective layers to reduce internal reflection or shaping the transparent casing into the form of lenses, mesas, gratings or nanowires [1][2][3][4][5][6][7][8][9][10] . These approaches help increase the critical angle of total internal reflection and/or reduce the Fresnel reflections at the interface.…”

Boost of single-photon emission by perfect coupling of InAs/GaAs quantum dot and micropillar cavity mode

“…Despite its advantages, the key issue to realize a practical QD single-photon source is how to further improve the brightness (i.e., count rates) of single photon source, which will greatly improve the efficiency of quantum information transmission [4]. Therefore, it is necessary to improve the extraction efficiency of QD emission and improve their brightness by means of coupling QDs with microcavities, including micropillars [11], microdisk [17], photonic crystals [18], and microstructures like microlenses [19][20][21][22]. Meanwhile, the light-matter interaction of different systems and the coupling effect in the visible and infrared range have been extensively studied [23][24][25][26][27].…”

Preparation of Graphene Quantum Dots and Their Sensing Properties in Quartz Crystal Microbalance Acetone Sensor

“…Top-down methods include electron beam lithography, acid oxidative stripping, microwave assistance, hydrothermal synthesis, and electrochemical oxidation. (18)(19)(20)(21) This preparation route has the advantages of abundant raw materials, simple operation, and mass production and the disadvantages of high requirements in terms of equipment, easy destruction of the aromatic structure of graphite, and the incapability of accurately controlling the form and size of the synthesized product. The bottom-up mechanism involves the assembly of small molecules into relatively large GQDs, with methods including the pyrolysis of polycyclic aromatic hydrocarbons, the use of a carbonized organic precursor, and solution chemistry.…”