Yasuhiko Arakawa

Yasuhiko Arakawa
The University of Tokyo | Todai · Institute of Industrial Scinence

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1,452
Publications
89,994
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41,467
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Publications

Publications (1,452)
Preprint
This study investigates the development of InAs quantum dot (QD) lasers on a InP(001) substrate, utilizing only III-arsenide layers. This approach avoids the issues associated with the use of phosphorus compounds, which are evident in the crystal growth of conventional C/L-band QD lasers, making the manufacturing process safer, simpler, and more co...
Article
Full-text available
In this work, we fabricate directly modulated membrane distributed reflector (DR) lasers on a Si waveguide by utilizing micro-transfer printing method. Micro-transfer printing enables low-loss coupling between the lasers and the silicon photonics circuit, and since it is a back-end process, we can test the lasers prior to integration. A membrane la...
Article
We perform a theoretical and numerical study of the optical properties of both direct and inverse three-dimensional (3D) chiral woodpile structures and a corresponding chiral Bragg stack, also known as a Reusch pile. We compute transmission spectra in the helical direction for finite crystals and photonic band structures, where we ensure the effect...
Article
Full-text available
We report hybrid integration of a telecom band InAs/InP quantum-dot (QD) single-photon source on a CMOS-processed Si photonics chip using transfer printing. The integration technique allows for the assemble of photonic components in a pick-and-place operation and therefore can introduce them on Si photonics chips after completing the entire CMOS-co...
Article
The ligands of quantum dots (QDs) not only play an important role in dispersion of the QDs in solvents and the protection of the QDs but could also block carrier injection into the QDs. Therefore, ligand engineering is important for improving performances of QD light-emitting diode (QLED) displays. In particular, exchange of an organic ligand with...
Chapter
This chapter describes the hybrid integration of quantum-dot single-photon sources (QD SPSs) on Si toward the scalable Si quantum photonics. In this study, transfer printing (TP) has been extensively investigated, a technique that simply relies on pick-and-place integration based on van der Waals force, and thus is fully compatible with the CMOS ba...
Preprint
Full-text available
We perform a theoretical and numerical study of the optical properties of both direct and inverse three-dimensional (3D) chiral woodpile structures, and a corresponding chiral Bragg stack. We compute transmission spectra in the helical direction for finite crystals, and photonic band structures, where we ensure the effective index of all structures...
Article
Slow light waveguides are advantageous for implementing high‐performance single‐photon sources required for scalable operation of integrated quantum photonic circuits (IQPCs), though such waveguides are known to suffer from propagation loss due to backscattering. A way to overcome the drawback is to use topological photonics, in which robust wavegu...
Article
Reflection high-energy electron diffraction (RHEED) is widely used because it allows in-situ observations of the surface behavior of a sample during molecular beam epitaxy (MBE) growth. In particular, RHEED patterns have been used for the calibration of growth conditions because they change considerably depending on the sample temperature, amount o...
Chapter
Three-dimensional photonic crystal (3D PhC) structure is one of the fascinating platforms providing versatile possibilities to manipulate photons and their interaction with materials. In particular, chiral 3D PhCs can modify the circularly polarized vacuum field inside the structures enabling the control of the interaction between materials and cir...
Preprint
Hybrid excitations of light and matter, namely, polaritons, in the ultrastrong coupling regime have been intensively investigated to explore novel material functions and realize coherent control of material properties by optical means. However, realization of ultrastrong coupling in a-few-electron systems has been challenging, because the electroni...
Article
Full-text available
Topological lasers have been intensively investigated as a strong candidate for robust single-mode lasers. A typical topological laser employs a single-mode topological edge state, which appears deterministically in a designed topological bandgap and exhibits robustness to disorder. These properties seem to be highly attractive in pursuit of high-p...
Article
Full-text available
We present an erratum to correct inadvertent errors in our paper [Opt. Express 29, 29378 (2021)10.1364/OE.433030]. The corrections do not affect the main conclusion.
Preprint
Slow light waveguides are advantageous for implementing high-performance single-photon sources required for scalable operation of integrated quantum photonic circuits (IQPCs), though such waveguides are known to suffer from propagation loss due to backscattering. A way to overcome the drawback is to use topological photonics, in which robust wavegu...
Article
Full-text available
We developed a micro-manipulation technique performed under optical microscope observation, which enabled accurate fabrication of three-dimensional photonic crystals for near-infrared light. Thin GaAs plates having an in-plane pattern were picked up with a fine needle and were mechanically stacked one-by-one by using vertical posts as guides. In sp...
Article
Full-text available
We report the discovery and characterization of single-photon-emitting carrier localization centers that are spontaneously formed along misfit dislocations in AlGaN. The emitters exhibit extremely narrow linewidths, which are in some cases narrower than our resolution limit of 35 µeV. Spectral analysis reveals a record-low inhomogeneous broadening...
Article
Full-text available
The H1 photonic crystal cavity supports two degenerate dipole modes of orthogonal linear polarization which could give rise to circularly polarized fields when driven with a π/2 phase difference. However, fabrication errors tend to break the symmetry of the cavity, which lifts the degeneracy of the modes, rendering the cavity unsuitable for support...
Article
Full-text available
We report a quantum-dot single-photon source (QD SPS) hybrid integrated on a silicon waveguide embedding a photonic crystal mirror, which reflects photons and enables efficient unidirectional output from the waveguide. The silicon waveguide is constituted of a subwavelength grating so as to maintain the high efficiency even under the presence of st...
Article
The introduction of a closely stacked quantum dot (QD) structure is considered as one of the most effective approaches to extend the emission wavelength of InAs/GaAs QDs beyond 1.3 μm (1300 nm). Here, we propose a tri-layer QD structure (three closely stacked QD layers) to further extend the emission wavelength of QDs and demonstrate room-temperatu...
Preprint
Full-text available
Topological lasers have been intensively investigated as a strong candidate for robust single-mode lasers. A typical topological laser employs a single-mode topological edge state, which appears deterministically in a designed topological bandgap and exhibits robustness to disorder. These properties seem to be highly attractive in pursuit of high p...
Article
Full-text available
With the development of dry fiber over the past two decades, the E-band has become a new telecommunication wavelength. However, owing to material constraints, an effective high-performance semiconductor light source has not yet been realized. InAs quantum dot (QD) lasers on GaAs substrates are in the spotlight as O-band light sources because of the...
Preprint
Full-text available
We report a quantum-dot single-photon source (QD SPS) hybrid integrated on a silicon waveguide embedding a photonic crystal mirror, which reflects photons and enables efficient unidirectional output from the waveguide. The silicon waveguide is constituted of a subwavelength grating so as to maintain the high efficiency even under the presence of st...
Preprint
Full-text available
The H1 photonic crystal cavity supports two degenerate dipole modes of orthogonal linear polarization which could give rise to circularly polarized fields when driven with a $\pi$/$2$ phase difference. However, fabrication errors tend to break the symmetry of the cavity which lifts the degeneracy of the modes, rendering the cavity unsuitable for su...
Article
Full-text available
Single-photon emitters with high degrees of purity are required for photonic-based quantum technologies. InGaN/GaN quantum dots are promising candidates for the development of single-photon emitters but have typically exhibited emission with insufficient purity. Here, pulsed single-photon emission with high purity is measured from an InGaN quantum...
Article
Full-text available
III-nitride quantum dot (QD) lasers have potential applications in visible light regime, yet one of its most important dynamic parameters, the linewidth enhancement factor (LEF), has been rarely studied. We studied the LEF of InGaN QD lasers with a comprehensive theory model and found that the LEF values of InGaN QD lasers can be smaller and more r...
Article
In this study, we evaluated the degradation mechanism in quantum dot light-emitting diodes (QLEDs) to improve the device lifetime. We measured the hole mobility using the delay time of transient electroluminescence for three types of hole transport layer (HTL) materials. In addition, we estimated the degradation of luminance efficiency and hole mob...
Article
Full-text available
Abstract InAs quantum dots (QDs) are receiving attention as next‐generation E‐band light source that offers high‐temperature operation and temperature insensitive operation. However, high‐density crystal defects occur at the interface between the InGaAs buffer layer and GaAs, resulting in reduced device performance and shortened lifetime. Here, E‐b...
Article
Full-text available
A full Poincaré (FP) beam possesses all possible optical spin states in its cross section, which constitutes an optical analog of a skyrmion. Until now FP beams have been exclusively generated using bulk optics. Here we propose a generation scheme of an FP beam based on an optical microring cavity. We position two different angular gratings along w...
Article
Full-text available
We experimentally demonstrate topological slow light waveguides in valley photonic crystals (VPhCs). We employed a bearded interface formed between two topologically-distinct VPhCs patterned in an air-bridged silicon slab. The interface supports both topological and non-topological slow light modes below the light line. By means of optical microsco...
Article
We present the design, fabrication, and detailed characterization of a photonic bullseye structure to enhance the single-photon extraction efficiency from self-Assembled GaN/AlN quantum dots (QDs) emitting in the UV. Through measurements of single-photon emission under saturated pulsed excitation at 80 MHz, we are able to evaluate photon extraction...
Preprint
We experimentally demonstrate topological slow light waveguides in valley photonic crystals (VPhCs). We employed a bearded interface formed between two topologically-distinct VPhCs patterned in an air-bridged silicon slab. The interface supports both topological and non-topological slow light modes below the light line. By means of optical microsco...
Article
When we applied colloidal quantum dots (QDs) for quantum dot light emitting diodes, it was well known that shell thickness played an important role in core protection, confinement of electrons and holes, and charge injection efficiency. However, although the shell thickness dependence of electroluminescence properties was reported, carrier injectio...
Article
Full-text available
Topological photonics provides a novel route for designing and realizing optical devices with unprecedented functionalities. Topological edge states, which are supported at the boundary of two photonic systems with different band topologies, enable robust light transport immune to structural imperfections and/or sharp bends in waveguides. Furthermo...
Article
The reflection high-energy electron diffraction (RHEED) method is widely used for the in situ observation of molecular beam epitaxy (MBE). This is because the RHEED pattern dynamically changes according to the growth conditions, such as surface temperature and material supply. However, to date, the RHEED pattern has been categorized and recognized...
Conference Paper
We report a topologically-protected single photon source in a slow light waveguide based on valley photonic crystals. Purcell-enhanced single photon generation from a quantum dot and its robust propagation in the topological waveguide are demonstrated.
Conference Paper
Non-Hermitian systems are open physical systems that could exchange energy with their surrounding environment.
Article
Full-text available
We identify and characterize a novel type of quantum emitter formed from InGaN monolayer islands grown using molecular beam epitaxy and further isolated via the fabrication of an array of nanopillar structures. Detailed optical analysis of the characteristic emission spectrum from the monolayer islands is performed, and the main transmission is sho...
Article
Full-text available
Solid-state devices capable of emitting single photons on demand are poised to allow the development of several photonic quantum technologies. Although high-performance devices have been reported in laboratory settings, the vast majority of experimental demonstrations performed to date have required the assistance of cryogenic cooling. In this pers...
Article
Full-text available
We demonstrate strong coupling between a single quantum dot (QD) and a GaAs-based L4/3-type photonic crystal nanocavity. The L4/3 cavity supports a high theoretical Q factor (∼8 × 10⁶), a small mode volume [∼0.32 (λ/n)³], and an electric field distribution with the maximum electric field lying within the host dielectric material, which facilitates...
Preprint
A full Poincar\'e (FP) beam possesses all possible optical spin states in its cross-section, which constitutes an optical analogue of a skyrmion. Until now, FP beams have been exclusively generated using bulk optics. Here, we propose a generation scheme of an FP beam based on an optical microring cavity. We position two different angular gratings a...
Preprint
We demonstrate strong coupling between a single quantum dot and a GaAs-based L4/3-type photonic crystal nanocavity. The L4/3 cavity supports a high theoretical Q factor (~8{\times}10^6), a small mode volume (~0.32 (\lambda/n)^3), and an electric field distribution with the maximum electric field lying within the host dielectric material, which faci...
Article
We study the optical reflectivity of real three-dimensional (3D) photonic band-gap crystals with increasing thickness. The crystals consist of GaAs plates with nanorod arrays that are assembled by an advanced stacking method into high-quality 3D woodpile structures. We observe intense and broad reflectivity peaks with stop bands that correspond to...
Article
Full-text available
Semiconductor quantum dots (QDs) of various material systems are being heavily researched for the development of solid state single photon emitters, which are required for optical quantum computing and related technologies such as quantum key distribution and quantum metrology. In this review article, we give a broad spectrum overview of the QD-bas...
Article
Reflection high-energy electron diffraction (RHEED) has wide application because it allows in situ observation of the sample surface behavior during molecular beam epitaxy growth (MBE). In particular, the RHEED pattern has been used as a mile-stone for growth condition calibration because it dynamically changes depending on the sample temperature,...
Article
We present a detailed analysis of the second-order correlation behavior of photons emitted from an InGaN QD in a photonic horn structure in order to discuss the excitation, emission, and environmental dynamics that impact the emission. We report the observation of a clear saturation in the antibunching decay rate as the excitation power is increase...
Article
Full-text available
Valley photonic crystals (VPhCs) are an attractive platform for the implementation of topologically protected optical waveguides in photonic integrated circuits (PICs). The realization of slow light modes in the topological waveguides may lead to further miniaturization and functionalization of the PICs. In this Letter, we report an approach to rea...
Article
Full-text available
Photonic crystal (PhC) nanocavities with high quality (Q) factors have attracted much attention because of their strong spatial and temporal light confinement capability. The resulting enhanced light–matter interactions are beneficial for diverse photonic applications, ranging from on-chip optical communications to sensing. However, currently achie...
Article
In this paper, the quantum dot intermixing (QDI) technique previously developed for 1550nm‐band InAs/InAlGaAs quantum dot (QD) was applied to 1200nm‐band InAs/GaAs QD. Three methods of defect introduction for triggering the QDI were employed such as ICP‐RIE (Ar⁺) and ion implantation (Ar⁺ and B⁺). As a result, about 80nm PL peak wavelength shift wa...
Article
Full-text available
Infrared (IR) spectral imaging is a powerful tool for component analysis and identification in the geological field. In this report, we originally use quantum dot infrared photodetector (QDIP) focal plane arrays (FPAs) with different peak-responsivity wavelengths to analyze the mineral composition of rock samples by IR spectral imaging and show the...
Article
Full-text available
Topological photonics emerged as a novel route to engineer the flow of light. Topologically protected photonic edge modes, which are supported at the perimeters of topologically nontrivial insulating bulk structures, are of particular interest as they may enable low-loss optical waveguides immune to structural disorder. Very recently, there has bee...
Article
Silicon quantum photonics provides a promising pathway to realize large-scale quantum photonic integrated circuits (QPICs) by exploiting the power of complementary-metal-oxide-semiconductor (CMOS) technology. Toward scalable operation of such silicon-based QPICs, a straightforward approach is to integrate deterministic single-photon sources (SPSs)....
Preprint
We study the optical reflectivity of three-dimensional (3D) photonic band gap crystals with increasing thickness. The crystals consist of GaAs plates with nanorod arrays that are assembled by an advanced stacking method into high-quality 3D woodpile structures. We observe intense and broad reflectivity peak with stop bands that correspond to a broa...
Article
According to the promotion of recent ubiquitous society, it is predicted that the transaction and transmission of information in supercomputers and data centers will rapidly increase. However, the problem of future capability in transaction and transmission of information is emerging by the extension of conventional LSIs’ progress. In this paper, w...
Conference Paper
We report efficient quantum-dot single-photon sources with unidirectional output integrated on Si by transfer printing. The device was designed to be robust against misalignment accompanied by the hybrid integration. Efficient single-photon generation was experimentally confirmed.
Conference Paper
We demonstrate slow light waveguides using topological valley kink states. We found in-gap high-group-index inodes at bearded interfaces of silicon-based valley photonic crystals, clearing the path to build topologically-protected slow light waveguides only using semiconductors.
Article
Topological photonics, an emerging field in photonics, is now receiving much attention not only due to its fundamental interests but also potential applications in integrated photonics. The concept of band topology originally developed in condensed matter physics provides a novel route for controlling light wave in periodic optical systems such as...
Article
Hybrid integration is a key technology for augmenting the functionality of integrated photonic circuits. Conventional hybrid integration approaches, such as wafer bonding and direct growth, offer the path for monolithic integration, but are often accompanied with significant complications in the integration processes. Here, we discuss a novel techn...
Preprint
Photonic crystal (PhC) nanocavities with high quality (Q) factors have attracted much attention because of their strong spatial and temporal light confinement capability. The resulting enhanced light-matter interactions are beneficial for diverse photonic applications, ranging from on-chip optical communications to sensing. However, currently achie...
Preprint
Full-text available
Topological photonics has emerged as a novel route to engineer the flow of light. Topologically-protected photonic edge modes, which are supported at the perimeters of topologically-nontrivial insulating bulk structures, have been of particular interest as they may enable low-loss optical waveguides immune to structural disorder. Very recently, the...
Preprint
Silicon quantum photonics provides a promising pathway to realize large-scale quantum photonic integrated circuits (QPICs) by exploiting the power of complementary-metal-oxide-semiconductor (CMOS) technology. Toward scalable operation of such silicon-based QPICs, a straightforward approach is to integrate deterministic single-photon sources (SPSs)....
Article
Growth of InAs quantum dots (QDs) in metamorphic InGaAs matrix for long‐wavelength laser applications on GaAs substrates by molecular beam epitaxy (MBE) is demonstrated. Metamorphic InGaAs matrix is based on a 5‐step graded InGaAs metamorphic buffer layer (MBL) with a final Indium composition of about 40%. Reciprocal lattice mapping for the asymmet...
Article
The cover image is based on the Original Article Single photon emission from a further confi ned InGaN/GaN quantum disc via reverse‐reaction growth by Xinqiang Wang et al., https://doi.org/10.1002/que2.20.
Article
Full-text available
In this work, we use photoluminescence (PL) spectroscopy to investigate how self-assembled GaSb/GaAs quantum dots (QDs) depend on their growth mechanism. Carrier transfer (i.e., carrier recombination in QDs and escape through the barrier layer) is investigated as a function of excitation-power- and temperature-dependent PL measurements. A drastic b...
Article
Full-text available
In this study, we examine a photonic wire waveguide embedded with an ensemble of quantum dots (QDs) that directionally emits into the waveguide depending on the spin state of the ensemble. The directional emission is facilitated by the spin-orbit interaction of light. The waveguide has a two-step stair-like cross section and QDs are embedded only i...
Article
We report the realization of single photon emission from an InGaN quantum dot in a GaN inverted truncated-pyramid structure: a single photon horn. The structural parameters of the quantum dots, especially the quantum confinement in the (0001) direction, are well controlled by optimizing the planar single InGaN quantum well to be of ∼2 monolayers. B...