A5065996866- Diamond and Carbon-based Materials Research
- Quantum Information and Cryptography
- Advanced Fiber Laser Technologies
- Photonic and Optical Devices
- Quantum optics and atomic interactions
- Quantum Mechanics and Applications
- Quantum Computing Algorithms and Architecture
- Force Microscopy Techniques and Applications
- Spectroscopy and Laser Applications
- High-pressure geophysics and materials
- Neural Networks and Reservoir Computing
- Spectroscopy Techniques in Biomedical and Chemical Research
- Metal and Thin Film Mechanics
- Laser-Matter Interactions and Applications
- Mechanical and Optical Resonators
- Electronic and Structural Properties of Oxides
- Advanced Materials Characterization Techniques
- Cold Atom Physics and Bose-Einstein Condensates
- Spectroscopy and Quantum Chemical Studies
- Semiconductor Quantum Structures and Devices
- Semiconductor Lasers and Optical Devices
- Semiconductor materials and devices
- Optical and Acousto-Optic Technologies
- Advanced Fiber Optic Sensors
- Thermal Radiation and Cooling Technologies
Kyoto University
2017-2025
The Japanese Society of Gastroenterological Surgery
2020-2023
Iwate Medical University
2020-2023
Hiroshima University Hospital
2023
Hudson Institute
2023
RELX Group (Netherlands)
2022
Kyoto Katsura Hospital
2017-2020
Showa University
2020
Jikei University School of Medicine
2020
University of KwaZulu-Natal
2016-2018
A diamond nano-crystal hosting a single nitrogen vacancy (NV) center is optically selected with confocal scanning microscope and positioned deterministically onto the subwavelength-diameter waist of tapered optical fiber (TOF) help an atomic force microscope. Based on this nano-manipulation technique, we experimentally demonstrate evanescent coupling fluorescence photons emitted by NV-center to guided mode TOF. By comparing photon count rates fiber-guided free-space modes numerical...
Nitrogen-vacancy (NV) centers in diamond have attracted significant interest because of their excellent spin and optical characteristics for quantum information metrology. To exploit these characteristics, precise control the orientation NV axis lattice is essential. Here we show that more than 99% can be aligned along [111] by chemical vapor deposition homoepitaxial growth on (111) substrates. We also discuss alignment mechanisms. Our result enables a fourfold improvement magnetic field...
We propose and experimentally demonstrate a transformation of two Einstein-Podolsky-Rosen photon pairs distributed among three parties into three-photon W state using local operations classical communication. then characterize the final quantum tomography on its marginal bipartite states. The fidelity to ideal is 0.778+/-0.043 expectation value for witness operator -0.111+/-0.043 implying success proposed transformation.
Optical illumination on negatively charged nitrogen-vacancy $(\mathrm{N}{\mathrm{V}}^{\ensuremath{-}})$ centers inevitably causes stochastic charge-state transitions between the $\mathrm{N}{\mathrm{V}}^{\ensuremath{-}}$ and neutral charge state of NV center. It limits steady-state population to 5% at minimum (\ensuremath{\sim}610 nm) 80% (\ensuremath{\sim}532 maximum in intrinsic diamond depending wavelength. Here, we show Fermi-level control by phosphorus doping generates 99.4...
Use of nitrogen-vacancy (NV) centers in diamond for quantum applications requires fast switching between their two different charge states. Using a diode, scientists now demonstrate the first time deterministic, purely electrical, and room-temperature charge-state control single NV on scale microsecond.
Harnessing the quantum interference of pair generation processes, infrared spectroscopy, based on nonlinear interferometers with visible-infrared photon-pair sources, enables extraction optical properties a sample through visible photon detection without need for an source or detector. We develop theoretical framework Fourier-transform (QFTIR) spectroscopy. The proposed Fourier analysis method, which fully utilizes phase information in interferogram, allows us to determine complex...
Spectroscopy in the mid-infrared region is an indispensable tool for identifying molecular types various fields, including physics, chemistry, and medical sciences. However, conventional infrared light sources, detectors, noise from blackbody radiation have been obstacles to miniaturization higher sensitivity of spectrometers. Quantum spectroscopy, which uses visible photon pairs a quantum entangled state, has attracted attention as new sensing technology that enables spectroscopy with...
We introduce an elementary optical gate for expanding polarization entangled $W$ states in which every pair of photons is alike. The composed a 50:50 beamsplitters and ancillary the two-photon Fock state. By seeding one $n$-photon state into this gate, we obtain $(n+2)$-photon after postselection. This gives better efficiency simpler implementation than previous proposals $W$-state preparation.
We introduce a simple optical gate to fuse arbitrary-size polarization entangled W-states prepare larger W-states. The requires polarizing beam splitter (PBS), half-wave plate (HWP) and two photon detectors. study, numerically analytically, the necessary resource consumption for preparing by fusing smaller ones with proposed fusion gate. show analytically that requirement scales at most sub-exponentially increasing size of state be prepared. determine cost without recycling where arbitrary...
We propose a simple probabilistic optical gate to expand polarization entangled W states. The uses one polarization-dependent beamsplitter and horizontally polarized single photon as an ancilla. post-selectively expands $N$-photon states $(N+1)$-photon A feasibility analysis considering the realistic experimental conditions show that scheme is within reach of current quantum technologies.
We demonstrate an optical gate that increases the size of polarization-based W states by accessing only one qubits. Using this gate, we have generated three-photon and four-photon with fidelities 0.836 ± 0.042 0.784 0.028, respectively. also confirmed existence pairwise entanglement in every pair qubits, including was left untouched gate. The is applicable to any hence a universal tool for expanding entanglement.
Dipole orientation in solid-state single photon emitters plays an important role applications such as quantum information devices integrated with nanophotonic components. In various emitters, hexagonal boron nitride (hBN) point defects is one of the most promising candidates a emitter for high photostability, ultrahigh brightness, nonlinearity, and narrow emission line width. applying hBN defect to those applications, three-dimensional determination its dipole critically important. this...
We derive the maximum success probability of circuits with passive linear optics for postselectively expanding an $N$-photon $W$ state to $(N+n)$-photon state, by accessing only one photon initial and adding $n$ photons in a Fock state. show that is achieved polarization-dependent beamsplitter $n\ensuremath{-}1$ polarization-independent beamsplitters.
Optically detected magnetic resonance (ODMR) is a way to characterize the NV centers. Recently, remarkably sharp dip was observed in ODMR with high-density ensemble of centers, and this reproduced by theoretical model [Zhu et al., Nature Communications 5, 3424 (2014)], showing that consequence spin-1 properties Here, we present much more details analysis show how can be applied investigate By using our model, have without fields. Also, theoretically affected typical parameters centers such...
We propose a simple setup for the conversion of multipartite entangled states in quantum network with restricted access. The scheme uses nonlocal operations to enable preparation that are inequivalent under local and classical communication, but most importantly does not require full access states. It is based on flexible linear optical gate photons, which ideally suited distributed computation communication extended networks. In order show basic working principles gate, we focus converting...
We report an experimental demonstration of wavelength variable generation and detection photon pairs in the visible mid-infrared (MIR) regions over a wide spectral range 2–5 µm via spontaneous parametric downconversion. Despite recent increase interest such photon-pair source, there have been few detailed evaluations emitted photons generated downconversion process low gain regime, due to lack suitable single-photon detectors. By changing angle nonlinear crystal, we continuously tune...
Infrared quantum absorption spectroscopy (IRQAS) enables the estimation of a sample's optical properties in infrared region, using only visible light source and detectors, which is technologically favorable. So far, spectral coverage IRQAS systems has been limited to less than 1 \textmu{}m. This work reports wavelength-tunable system an efficient measurement scheme achieve broadband short acquisition time. The successful demonstration rapid over wide midinfrared window (1.9--5.2 \textmu{}m)...
Nanodiamonds containing silicon-vacancy (SiV) centers with high brightness, photo-stability, and a narrow zero phonon line (ZPL) have attracted attention for bioimaging, nanoscale thermometry, quantum technologies. One method to create such nanodiamonds is the milling of diamond films synthesized by chemical vapor deposition (CVD). However, this requires post-processing as acid treatment centrifugation after process. Therefore, number SiV center-containing made from an initial CVD small. An...
We propose and demonstrate a scheme for boosting the efficiency of entanglement distribution based on decoherence-free subspace over lossy quantum channels. By using backward propagation coherent light, our achieves an entanglement-sharing rate that is proportional to transmittance T channel in spite encoding qubits multipartite systems subspace. experimentally show highly entangled states, which can violate Clauser-Horne-Shimony-Holt inequality, are distributed at T.
Nanofiber Bragg cavities (NFBCs) are solid-state microcavities fabricated in an optical tapered fiber. NFBCs promising candidates as a platform for photonic quantum information devices due to their small mode volume, ultra-high coupling efficiencies, and ultra-wide tunability. However, the quality (Q) factor has been limited be approximately 250, which may limitations fabrication process. Here we report high Q using focused helium ion beam. Whenan NFBC with grooves of 640 periods is...
We experimentally demonstrate the active control of a plasmonic metamaterial operating in quantum regime. A two-dimensional consisting unit cells made from gold nanorods is investigated. Using an external laser, we temperature and carry out process tomography on single-photon polarization-encoded qubits sent through, characterizing as variable channel. The overall polarization response can be tuned by up to 33% for particular nanorod dimensions. To explain results, develop theoretical model...
A nanodiamond embedding a single nitrogen-vacancy (NV) center has outstanding optical properties since it is readily manipulated and coupled with nanophotonic devices. Reliable methods to identify the orientation of an NV axis on photonic platforms are important precisely estimate coupling efficiency between them. We report method axis. The proposed consists dataset optically detected magnetic resonance (ODMR) measurements taken while rotating field in plane ODMR measurement applying...
Abstract Nitrogen-vacancy (NV) centres in diamond hold promise quantum sensing applications. A major interest them is an enhancement of their sensitivity by the extension coherence time ( T 2 ). In this report, we experimentally generated more than four dressed states a single NV centre based on Autler-Townes splitting (ATS). We also observed to ~ 1.5 ms which two orders magnitude longer that undressed states. As example application using these results propose protocol sensing, shows order...