Unidirectional Emission of a Site-Controlled Single Quantum Dot from a Pyramidal Structure

Abstract

Emission control of a quantum emitter made of semiconductor materials is of significance in various optical applications. Specifically, the realization of efficient quantum emitters is important because typical semiconductor quantum dots are associated with low extraction efficiency levels due to their high refractive index contrast. Here, we report bright and unidirectional emission from a site-controlled InGaN quantum dot formed on the apex of a silver-coated GaN nanopyramidal structure. We show that the majority of the extracted light from the quantum dot is guided toward the bottom of the pyramid with high directionality. We also demonstrate that nanopyramid structures can be detached from a substrate, thus demonstrating great potential of this structure in various applications. To clarify the directional radiation, the far-field radiation pattern is measured using Fourier microscopy. This scheme will pave the way toward the realization of a bright and unidirectional quantum emitter along with easy fabrication and large-area reproducibility.

Room temperature solid-state quantum emitters in the telecom range

“…The data are fit well using the three level system with an equation I(P)=I∞×P/(P+Ps), where () To study the effect of the PSS on the extraction efficiency, 3D finite difference time domain (FDTD) optical simulation (using Lumerical software) is carried out for the defect embedded in a pristine GaN and the one grown on a PSS. Based on the simulation results, the far field pattern and the collection efficiency can be obtained 25 . For the bare GaN substrate, a model consisting of a GaN layer (refractive index = 2.33) on top of sapphire layer (refractive index = 1.75) in an immersion oil environment (refractive index = 1.52) is assumed.…”

Nanoassembly of quantum emitters in hexagonal boron nitride and gold nanospheres

“…Plasmonic nanoantennas are advantageous among a variety of optical resonators due to their broad spectral resonances, which make spectral matching between the optical mode and an emitter substantially less complicated. 3,[16][17][18] Although plasmonic resonances have low Qfactors compared with dielectric cavities, they provide high Purcell enhancements due to small mode volumes, 3,19 also known as 'hot spots'. Several techniques including electron beam lithography, 20 optical trapping of quantum emitters on top of metal nanoantennas 21 and wet chemical transfer 17 have been previously explored for deterministic assembly of hybrid quantum nanophotonic-plasmonic devices.…”

Semiconductor nanopyramids for building high-yield quantum photonic devices

“…In our more recent work, we have also suggested that site-controlled QDs in nanopyramid structures can be used as a unidirectional single-photon source. 5 To thus realize downward-guided emitted light from a QD, we conformally deposited silver films on the nanopyramids. We also confirmed numerically that the QD at the apex exhibited unidirectional emission toward the bottom of the structure (see Figure 3).…”

“…Specifically, we (top) and lower (bottom) hemispheres-from a single QD in a pyramidal structure (depicted center) that is covered by a conformally deposited Ag film. 5 : Wavelength. E: Energy.…”