ORCID Profile
0000-0001-9836-3608
Current Organisation
University of Melbourne
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Publisher: IOP Publishing
Date: 18-02-2021
Abstract: Photonic cavities are valued in current research owing to the multitude of linear and nonlinear effects arising from densely confined light. Cavity designs consisting of low loss dielectric materials can achieve significant light confinement. Until now, the basic concepts in all-dielectric photonics such as anapole resonances have been primarily studied in high index materials. Here, we use photonic simulation to propose fabricable designs for higher confinement in low index dielectric cavities by incorporating the extensively studied isolated dielectric nanodisk into broader host structures. We further discuss on hexagonal boron nitride nanodisks for their potential use in quantum and nanophotonics applications.
Publisher: Walter de Gruyter GmbH
Date: 08-02-2022
Abstract: Nanowires have garnered considerable attention in photonics and optoelectronics due to their unique features. Owing to the large surface area and significant potential of usage as a resonator and waveguide in photonic integrated circuits (PICs), nanowires have been applied in many research areas in nanophotonics. To enhance the properties of light emitting materials, the hybrid of nanowires and 2D materials has been deployed in many papers. This paper summarises recent studies on the application of various types of nanowires in photonics and optoelectronics, as well as the combination of nanowires and 2D materials. This review article introduces nanowires that act as resonators or/and waveguides to increase the performance of 2D materials used in PICs for light enhancement and guiding. Moreover, the review lays out the hybrid of nanowires and 2D materials that have been studied in the field of optoelectronics. The hybridization of nanowires and 2D materials for photonics and optoelectronics is discussed in this review for the outlook of future studies.
Publisher: American Chemical Society (ACS)
Date: 20-09-2016
DOI: 10.1021/ACS.NANOLETT.6B02331
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.
Publisher: Wiley
Date: 13-01-2023
Abstract: 2D materials, with distinct characteristics compared to their conventional bulk counterparts, have been a popular topic in various optoelectronic research fields. Herein, indium selenide (InSe), a monochalcogenide van der Waals layered semiconductor, which has been studied due to its thickness dependent optical characteristics is explored. For InSe to be used as a versatile light source, enhancing the emission of InSe is required. Here, enhanced photoluminescence (PL) from multi‐layer InSe is demonstrated using a gap plasmon induced between Ag nanocube dimer and an Au substrate. Such plasmonic structures support multiple resonances, one of those overlapping with InSe's band edge PL emission. The calculated Purcell factor shows a 200‐fold increase on the short edge of nanocube dimers. Experimentally, PL enhancement of 6‐fold is demonstrated at room temperature. In addition, a method for determining the thickness of 2D materials via dark‐field spectroscopy using white light illumination is shown. This study paves the way for the incorporation of 2D InSe into nanophotonic structures.
Publisher: Springer Science and Business Media LLC
Date: 07-10-2020
DOI: 10.1038/S41467-020-18749-2
Abstract: Modifying material properties at the nanoscale is crucially important for devices in nano-electronics, nanophotonics and quantum information. Optically active defects in wide band gap materials, for instance, are critical constituents for the realisation of quantum technologies. Here, we demonstrate the use of recoil implantation, a method exploiting momentum transfer from accelerated ions, for versatile and mask-free material doping. As a proof of concept, we direct-write arrays of optically active defects into diamond via momentum transfer from a Xe + focused ion beam (FIB) to thin films of the group IV dopants pre-deposited onto a diamond surface. We further demonstrate the flexibility of the technique, by implanting rare earth ions into the core of a single mode fibre. We conclusively show that the presented technique yields ultra-shallow dopant profiles localised to the top few nanometres of the target surface, and use it to achieve sub-50 nm positional accuracy. The method is applicable to non-planar substrates with complex geometries, and it is suitable for applications such as electronic and magnetic doping of atomically-thin materials and engineering of near-surface states of semiconductor devices.
Publisher: The Optical Society
Date: 10-11-2011
DOI: 10.1364/OE.19.024055
Publisher: AIP Publishing
Date: 19-07-2021
DOI: 10.1063/5.0046084
Abstract: Semiconductor quantum dots (QDs) integrated with photonic nanowires are one of the representative platforms for high-purity single photonic sources. However, conventional photonic nanowires suffer from severe scattering at the edge owing to the small footprint. For this reason, tapered structures have been adopted to achieve directional emission with minimized scattering, and hence, high light collection efficiency. So far, various tapered structures have been demonstrated by using top-down etching fabrication or catalyst-assisted growth. However, these approaches can induce critical issues for QD integrated photonic devices such as an etching damage, an inclusion of multiple QDs in a wire, a misalignment of QD with respect to the wire axis center, or a contamination of QD by the catalyst. Therefore, developing a catalyst-free, site-controlled growth technique is essential for high-quality tapered nanowire structures. In this work, we propose a site-selectively grown photonic rocket structure, which consists of a pencil-like nanowire and a pyramid acting as a single-mode waveguide and a coupler, respectively. Since this structure is defined by stable crystal facets, the dimensions of the structure, especially its tapering angle, are determined precisely. Most significantly, a single QD can be formed at the apex, deterministically aligned to the axis center of the photonic structure. We analyzed the propagating mode inside the photonic nanowire and pyramid coupler using finite-difference time-domain simulations. This photonic rocket structure produces directional emission owing to the pyramid coupler, resulting in 2.9 (2.0) times larger light collection efficiency with a numerical aperture of 0.3 (0.7), compared to the nanowire structure alone.
Publisher: Beilstein Institut
Date: 09-01-2018
DOI: 10.3762/BJNANO.9.12
Abstract: We propose and design photonic crystal cavities (PCCs) in hexagonal boron nitride (hBN) for erse photonic and quantum applications. Two dimensional (2D) hBN flakes contain quantum emitters which are ultra-bright and photostable at room temperature. To achieve optimal coupling of these emitters to optical resonators, fabrication of cavities from hBN is therefore required to maximize the overlap between cavity optical modes and the emitters. Here, we design 2D and 1D PCCs using anisotropic indices of hBN. The influence of underlying substrates and material absorption are investigated, and spontaneous emission rate enhancements are calculated. Our results are promising for future quantum photonic experiments with hBN.
Publisher: Optica Publishing Group
Date: 09-11-2020
DOI: 10.1364/OME.409488
Abstract: Deterministic quantum dots (apex-QDs), which are spontaneously formed at the vertex of pyramid structures, are an attractive single-photon source. Herein, we propose the design of apex-QDs coupled to a single-mode optical fiber for directional emission from a quantum dot, followed by optimization of the structural parameters to maximize the extraction efficiency toward the fiber using FDTD simulation. A dielectric layer of SiO 2 was inserted between a silver and a quantum dot to minimize the metallic loss and control the distance between them. For this, the optimum layer thicknesses of silver and SiO 2 were 100 nm and 240 nm, respectively, achieving 94% light collection downward near 600 nm in wavelength. The proposed structure was then coupled to a tapered optical fiber, achieving 60% of the quantum dot emission. This high collection through an optical fiber was observed for a wide range of emission wavelengths.
Publisher: Wiley
Date: 27-11-2022
Abstract: Integration of solid‐state quantum emitters into nanophotonic circuits is a critical step towards fully on‐chip quantum photonic‐based technologies. Among potential materials platforms, quantum emitters in hexagonal boron nitride (hBN) have emerged as a viable candidate over the last years. While the fundamental physical properties have been intensively studied, only a few works have focused on the emitter integration into photonic resonators. Yet, for a potential quantum photonic material platform, the integration with nanophotonic cavities is an important cornerstone, as it enables the deliberate tuning of the spontaneous emission and the improved readout of distinct transitions for a quantum emitter. In this work, the resonant tuning of a monolithic cavity integrated hBN quantum emitter is demonstrated through gas condensation at cryogenic temperature. In resonance, an emission enhancement and lifetime reduction are observed, with an estimate for the Purcell factor of ≈15.
Publisher: Optica Publishing Group
Date: 03-02-2020
DOI: 10.1364/OME.389490
Abstract: Single photons and in idual quantum systems are at the heart of recent developments in quantum technologies and are about to enable a variety of novel applications in sensing, communication, and computing. Photonic devices are the key to control interactions between quantum systems and light as well as to simultaneously engineer the properties of photons. For scalable quantum technologies, the employed quantum systems are solid-state based, thus placing the field of quantum photonics at the intersection of physics, nanotechnology, and material sciences. This special issue features 14 contributions and addresses recent advances in several material platforms.
Publisher: American Chemical Society (ACS)
Date: 21-07-2021
Publisher: American Chemical Society (ACS)
Date: 24-01-2019
DOI: 10.1021/ACS.NANOLETT.8B04956
Abstract: Hexagonal boron nitride (hBN) is an emerging layered material that plays a key role in a variety of two-dimensional devices, and has potential applications in nanophotonics and nanomechanics. Here, we demonstrate the first cavity optomechanical system incorporating hBN. Nanomechanical resonators consisting of hBN beams with average dimensions of 12 μm × 1.2 μm × 28 nm and minimum predicted thickness of 8 nm were fabricated using electron beam induced etching and positioned in the optical near-field of silicon microdisk cavities. Of the multiple devices studied here a maximum 0.16 pm/[Formula: see text] sensitivity to the hBN nanobeam motion is demonstrated, allowing observation of thermally driven mechanical resonances with frequencies between 1 and 23 MHz, and largest mechanical quality factor of 1100 for a 23 MHz mode, at room temperature in high vacuum. In addition, the role of air d ing is studied via pressure dependent measurements. Our results constitute an important step toward realizing integrated optomechanical circuits employing hBN.
Publisher: American Chemical Society (ACS)
Date: 24-02-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7NR08249E
Abstract: The assembly of quantum nanophotonic systems with plasmonic resonators is important for fundamental studies of single photon sources as well as for on-chip information processing.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2NA00732K
Abstract: Two-dimensional (2D) materials are extensively studied in almost all scientific research areas, from fundamental research to applications. In this review, photonic devices that solely consist of 2D materials are introduced.
Publisher: American Chemical Society (ACS)
Date: 20-08-2021
Publisher: American Chemical Society (ACS)
Date: 30-09-2021
Publisher: Springer Science and Business Media LLC
Date: 28-02-2018
DOI: 10.1038/S41467-018-03290-0
Abstract: Layered van der Waals materials are emerging as compelling two-dimensional platforms for nanophotonics, polaritonics, valleytronics and spintronics, and have the potential to transform applications in sensing, imaging and quantum information processing. Among these, hexagonal boron nitride (hBN) is known to host ultra-bright, room-temperature quantum emitters, whose nature is yet to be fully understood. Here we present a set of measurements that give unique insight into the photophysical properties and level structure of hBN quantum emitters. Specifically, we report the existence of a class of hBN quantum emitters with a fast-decaying intermediate and a long-lived metastable state accessible from the first excited electronic state. Furthermore, by means of a two-laser repumping scheme, we show an enhanced photoluminescence and emission intensity, which can be utilized to realize a new modality of far-field super-resolution imaging. Our findings expand current understanding of quantum emitters in hBN and show new potential ways of harnessing their nonlinear optical properties in sub-diffraction nanoscopy.
Publisher: American Chemical Society (ACS)
Date: 13-05-2020
Publisher: The Optical Society
Date: 03-12-2014
DOI: 10.1364/OE.22.030707
Publisher: Springer Science and Business Media LLC
Date: 12-07-2021
Publisher: The Optical Society
Date: 20-02-2014
DOI: 10.1364/OE.22.004699
Publisher: American Association for the Advancement of Science (AAAS)
Date: 02-03-2018
Abstract: An optically stable, room temperature single-photon emitter operating in telecom wavelength range is discovered in GaN.
Publisher: Springer Science and Business Media LLC
Date: 05-07-2018
DOI: 10.1038/S41467-018-05117-4
Abstract: Development of scalable quantum photonic technologies requires on-chip integration of photonic components. Recently, hexagonal boron nitride (hBN) has emerged as a promising platform, following reports of hyperbolic phonon-polaritons and optically stable, ultra-bright quantum emitters. However, exploitation of hBN in scalable, on-chip nanophotonic circuits and cavity quantum electrodynamics (QED) experiments requires robust techniques for the fabrication of high-quality optical resonators. In this letter, we design and engineer suspended photonic crystal cavities from hBN and demonstrate quality ( Q ) factors in excess of 2000. Subsequently, we show deterministic, iterative tuning of in idual cavities by direct-write EBIE without significant degradation of the Q -factor. The demonstration of tunable cavities made from hBN is an unprecedented advance in nanophotonics based on van der Waals materials. Our results and hBN processing methods open up promising avenues for solid-state systems with applications in integrated quantum photonics, polaritonics and cavity QED experiments.
Publisher: Wiley
Date: 13-08-2020
Publisher: AIP Publishing
Date: 30-10-2023
DOI: 10.1063/5.0159264
Publisher: Springer Science and Business Media LLC
Date: 12-11-2020
Publisher: The Optical Society
Date: 27-11-2019
DOI: 10.1364/OL.44.005792
Publisher: Optica Publishing Group
Date: 22-01-2021
DOI: 10.1364/OL.416564
Abstract: Hexagonal boron nitride (hBN) is a layered dielectric material with a wide range of applications in optics and photonics. In this work, we demonstrate a fabrication method for few-layer hBN flakes with areas up to 5000 µ m 2 . We show that hBN in this form can be integrated with photonic microstructures: as an ex le, we use a circular Bragg grating (CBG). The layer quality of the exfoliated hBN flake on and off a CBG is confirmed by Raman spectroscopy and second-harmonic generation (SHG) microscopy. We show that the SHG signal is uniform across the hBN s le outside the CBG and is lified in the center of the CBG.
Publisher: American Chemical Society (ACS)
Date: 30-04-2021
Publisher: The Optical Society
Date: 25-07-2019
DOI: 10.1364/OL.44.003797
Publisher: American Chemical Society (ACS)
Date: 12-06-2020
Publisher: Massachusetts Medical Society
Date: 26-08-2021
Publisher: Wiley
Date: 22-09-2016
Abstract: Direct integration of semiconductor photonic nanocavities with paper substrates is demonstrated for the first time. 1D photonic crystal nanocavities successfully show lasing action on paper substrates. The device has great synergy as a sensor because paper has good wicking ability while a photonic crystal cavity has high figure of merit. The research provides a platform for eco-friendly and sustainable devices.
Publisher: The Optical Society
Date: 10-11-2015
DOI: 10.1364/OL.40.005351
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7NR08222C
Abstract: Ar plasma etching and annealing are highly robust in generating oxygen related single photon emitters in hBN.
Publisher: Wiley
Date: 12-09-2019
Location: Korea, Republic of
No related grants have been discovered for Sejeong Kim.