A5064777053- Photonic and Optical Devices
- Quantum Mechanics and Non-Hermitian Physics
- Neural Networks and Reservoir Computing
- Photonic Crystals and Applications
- Nonlinear Photonic Systems
- Optical Network Technologies
- Quantum Information and Cryptography
- Quantum Computing Algorithms and Architecture
- Advanced Fiber Laser Technologies
- Semiconductor Lasers and Optical Devices
- Topological Materials and Phenomena
- Plasmonic and Surface Plasmon Research
- Advanced Photonic Communication Systems
- Spectroscopy and Quantum Chemical Studies
- ZnO doping and properties
- Metamaterials and Metasurfaces Applications
- Electronic and Structural Properties of Oxides
- Optical Wireless Communication Technologies
- Particle Accelerators and Free-Electron Lasers
- Laser-Matter Interactions and Applications
- Laser Design and Applications
- Advancements in Semiconductor Devices and Circuit Design
- Nonlinear Waves and Solitons
- Advanced Antenna and Metasurface Technologies
- Photorefractive and Nonlinear Optics
NTT Basic Research Laboratories
2017-2025
NTT (Japan)
2018-2025
NeoPhotonics (United States)
2022
Nanophoton (Brazil)
2022
Japan Science and Technology Agency
2015-2016
National Institute of Informatics
2011-2015
The University of Tokyo
2011-2015
Tokyo University of Information Sciences
2014
Saga University
2012
SPring-8
2004
We reveal a one-dimensional topological insulating phase induced solely by gain and loss control in non-Hermitian optical lattices. The system comprises units of four uniformly coupled cavities, where the successive two have loss; others experience gain, they are balanced under magnitudes. parts effectively dimerized, bulk band gap, transition, midgap edge, interface states finite systems can all be achieved controlled pumping. also clarify invariants edge gapless conditions.Received 25...
We propose a mapping protocol to implement Ising models in injection-locked laser systems. The proposed scheme is based on optical coherent feedback and can be potentially applied for large-scale problems.
Topological photonics has emerged as a novel route to engineer the flow of light. Topologically-protected photonic edge modes, which are supported at perimeters topologically-nontrivial insulating bulk structures, have been particular interest they may enable low-loss optical waveguides immune structural disorder. Very recently, there is sharp rise in introducing gain materials into such topological primarily aiming revolu-tionizing semiconductor lasers with aid physical mechanisms existing...
Controlling gain and loss of coupled optical cavities can induce non-Hermitian degeneracies eigenstates, called exceptional points (EPs). Various unconventional phenomena around EPs have been reported, are expected to incorporate extra functionalities into photonic devices. The eigenmode exactly under EP degeneracy is also predicted exhibit enhanced radiation. However, such responses yet be observed in on-chip lasers because both the limited controllability their lifting by pump-induced...
The concept of bound states in the continuum (BIC) has been advancing light confinement technology leaky environments. In this Letter, we propose and numerically demonstrate a slow waveguide based on BIC mode. We considered with polymer core loaded plane slab, which supports guided mode coupled to radiation slab. found that periodic modulation along propagation direction can result high group index low loss due confinement. introduction one-dimensional photonic crystals into waveguides will...
Many tasks in our modern life, such as planning an efficient travel, image processing and optimizing integrated circuit design, are modeled complex combinatorial optimization problems with binary variables. Such can be mapped to finding a ground state of the Ising Hamiltonian, thus various physical systems have been studied emulate solve this problem. Recently, networks mutually injected optical oscillators, called coherent machines, developed promising solvers for problem, benefiting from...
We theoretically and numerically study the quantum dynamics of two degenerate optical parametric oscillators with mutual injections. The cavity mode in coupling path between oscillator facets is explicitly considered. Stochastic equations for injection based on positive $P$ representation are derived. system gradually pumped out-of-phase injections simulated, its state investigated. When incoherent loss other than small, squeezed quadratic amplitudes $\stackrel{\ifmmode \hat{}\else...
Abstract Nonlinear optical gates are usually considered as fundamental building blocks for universal computation. However, the performance is severely limited by small nonlinearity, thereby bounding their operation speed, consumption energy, and device size. In this paper, we propose experimentally demonstrate linear logic operations with ~3 μm-long Si wire “Ψ” consist of 3 × 1 combiners including auxiliary bias port, which maximizes binary contrast output in telecom wavelength. We have...
We numerically study the dynamics and frequency response of recently proposed Ising machine based on polarization degrees freedom an injection-locked laser network (Utsunomiya et al 2011 Opt. Express 19 18091). simulate various anti-ferromagnetic problems, including ones with symmetric Zeeman coefficients, which enable us to problem size up M = 1000. Transient time, reach a steady-state configuration after given is mapped onto system, inversely proportional locking bandwidth does not scale...
Exceptional point (EP) degeneracies in coupled cavities with gain and loss provide on-chip photonic devices unconventional features performance. However, such systems realistic structures often miss the exact EPs even simulation, mechanism of this EP disruption has yet to be thoroughly identified. Here we extend coupled-mode theory one-dimensional non-Hermitian resonator arrays study effects imaginary part intercavity coupling, which is a second-order term attributed material amplification,...
Recently, coherent control of absorption in metallic metasurfaces has been demonstrated, and this phenomenon was applied to intriguing light-by-light switching operation. Here we experimentally demonstrate beam deflection by high-efficiency for the first time. Although efficiency a metasurface is generally small, metasurfaces, which consist single layer with back reflector, are known exhibit significantly high efficiency. A key point our study replace reflector partial instead, enables pair...
The authors study coupled resonator optical waveguides (CROWs) to extend control of light propagation in photonic devices. Exploiting parity-time ($\mathcal{P}\phantom{\rule{0}{0ex}}\mathcal{T}$) symmetry the waveguide allows selection group velocity and its dispersion for cavity modes. researchers describe a scalable, controllable CROW with $\mathcal{P}\phantom{\rule{0}{0ex}}\mathcal{T}$ symmetry, which is induced by periodic balanced amplification absorption, analyze potential switching...
To clarify the whole picture of valence-band structures prototype ferromagnetic semiconductors (III,Mn)As (III: In and Ga), we perform systematic experiments resonant tunneling spectroscopy on [(In${}_{0.53}$Ga${}_{0.47}$)${}_{1\ensuremath{-}x}$Mn${}_{x}$]As ($x$ $=$ 0.06--0.15) In${}_{0.87}$Mn${}_{0.13}$As grown AlAs/In${}_{0.53}$Ga${}_{0.47}$As:Be/${p}^{+}$InP(001). We show that valence band almost remains unchanged from host semiconductor (In${}_{0.53}$Ga${}_{0.47}$)As, Fermi level exists...
We study two operational schemes for a coherent Ising machine based on an injection-locked laser network. These gradually increase the pumping rate or mutual coupling among slave lasers. numerically simulate against data search problem implemented with model in cubic graphs without frustration. show that can achieve better success probability and effective computational time to find target ground state these gradual than those abrupt introduction of injection which has been studied...
Experimental studies have been made of the spectral change with excitation and linewidth room temperature (Ga Al)As-Ga As heterostructure lasers. The lasers stripe geometry configuration show uniform near-field patterns single axial mode operations in relatively wide ranges current levels. Continuous output powers several to 20 mW (from one facet) obtained under at levels below 500 mA. data on excitation-dependent indicate that laser line is homogeneously broadened diffusion inverted...
A two-site Ising model is implemented as an injection-locked laser network consisting of a single master and two mutually coupled slave lasers. We observed ferromagnetic antiferromagnetic orders in the in-phase out-of-phase couplings between Their phase difference locked to either 0 or π even if coupling path continuously modulated. The system automatically selects oscillation frequency satisfy condition, when mutual dominates over injection-locking by laser.
The Kuramoto model is a mathematical for describing the collective synchronization phenomena of coupled oscillators. We theoretically demonstrate that an array photonic crystal lasers emulates with non-delayed nearest-neighbor coupling (the local model). Our novel strategy employs indirect between via additional cold cavities. By installing cavities laser cavities, we avoid strong and realize ideal mutual injection-locking effective dissipative coupling. First, after discussing limit cycle...
An H1 photonic crystal nanocavity is based on a single point defect and has eigenmodes with variety of symmetric features. Thus, it promising building block for tight-binding lattice systems that can be used in studies condensed matter, non-Hermitian topological physics. However, improving its radiative quality ($Q$) factor been considered challenging. Here, we report the design hexapole mode an $Q$ exceeding $10^8$. We achieved such extremely high-$Q$ conditions by designing only four...
We comment on the recent paper "Reconciling results of tunnelling experiments (Ga,Mn)As" arXiv:1102.3267v2 by Dietl and Sztenkiel. They claimed that oscillations observed in d2I/dV2-V characteristics our studies resonant tunneling spectroscopy GaMnAs, are not attributed to levels GaMnAs layer but two-dimensional interfacial subbands GaAs:Be layer. Here, we show this interpretation is able explain experimental conclusions remain unchanged.