A5049583155- Adaptive optics and wavefront sensing
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum, superfluid, helium dynamics
- Astronomy and Astrophysical Research
- Terahertz technology and applications
- Optical Systems and Laser Technology
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Photonic and Optical Devices
- Orbital Angular Momentum in Optics
- Advanced Fiber Laser Technologies
- Calibration and Measurement Techniques
- Atomic and Subatomic Physics Research
- Optical Wireless Communication Technologies
- Inertial Sensor and Navigation
- Metamaterials and Metasurfaces Applications
- Mechanical and Optical Resonators
- Photonic Crystals and Applications
- Plasmonic and Surface Plasmon Research
- Spectroscopy and Laser Applications
- Laser-Matter Interactions and Applications
- Superconducting and THz Device Technology
- Electron and X-Ray Spectroscopy Techniques
- Quantum Information and Cryptography
- Transition Metal Oxide Nanomaterials
Osaka University
2015-2025
Kyoto University
2006-2025
Las Cumbres Observatory Global Telescope Network
2018-2022
Japan Science and Technology Agency
2020-2022
National Astronomical Observatory of Japan
2011-2019
National Institutes of Natural Sciences
2011-2019
Kavli Institute for the Physics and Mathematics of the Universe
2018
California Institute of Technology
2018
Subaru (Japan)
2016-2017
The University of Tokyo
2005
The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is a multipurpose high-contrast imaging platform designed for the discovery and detailed characterization of exoplanetary systems serves as testbed technologies ELTs. It multi-band which makes use light from 600 to 2500nm allowing coronagraphic direct exoplanet inner 3 lambda/D stellar host. Wavefront sensing control are key operation SCExAO. A partial correction low-order modes provided by Subaru's facility adaptive optics...
Intense ultrashort light pulses induce three dimensional localized phase transformation of diamond. Photoinduced amorphous structures have electrical conducting properties a maximum 64 S/m based on transition from sp(3) to sp(2) in The laser parameters fluence and scanning speed affect the resultant conductivities due recrystallization multi-filamentation phenomena. We demonstrate that laser-processed diamond with periodic cylinder arrays characteristic transmission terahertz region, which...
Terahertz spectroscopy is one of the most suitable methods for analysis electron transport in solids, and has been applied to various materials. Here, we demonstrate that terahertz technique choice characterize solid electrolytes. We measure conductivity stabilized zirconia, a widely used electrolyte material, by time-domain at high temperatures, providing wealth information unavailable from conventional techniques. It found reflects microscopic motion ion just before hopping an unoccupied...
We propose a simple achromatic terahertz wave plate composed of stacked parallel metal plates with hole array. It consists an ensemble designed waveguides; the high and low propagation speeds waves in TE TM waveguide modes same group velocity cause constant phase difference over wide frequency region. Using that plate, we obtained intense single- multi-cycle THz pulses circular polarization.
PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting prime focus, 2394 reconfigurable fibers will be distributed over 1.3 deg field of view. The spectrograph has been designed with 3 arms blue, red, cameras to simultaneously observe spectra from 380nm 1260nm in one exposure at resolution ~ 1.6-2.7Å. An international collaboration developing this...
We established a novel method to evaluate effective optical constants by terahertz (THz) time domain spectroscopy and suggested strict definition of an expression for electromagnetic energy loss following the second law thermodynamics. deduced phosphor bronze wire grids in THz region experimentally theoretically. The results depend strongly on polarization waves. When electric field is parallel wires, we observed Drude-like permittivities with plasma frequency reduced factor 10(-3), whereas...
We demonstrate for the first time an efficient, photonic-based astronomical spectrograph on 8-m Subaru Telescope.An extreme adaptive optics system is combined with pupil apodiziation to efficiently inject light directly into a single-mode fiber, which feeds compact cross-dispersed based array waveguide grating technology.The instrument currently offers throughput of 5% from sky-to-detector we outline could easily be upgraded ∼ 13% (assuming coupling efficiency 50%).The isolated fiber...
Although nanoparticles have been used to study the properties of superfluid helium as fluid tracers, interaction between and has remained largely unexplored. This is due lack a technique precisely trap manipulate in helium. Optical tweezers, three-dimensional confinement nanoparticle by strongly focused beam light, widely employed investigating biomaterial nanomechanics, nanoscopic properties, ultrasensitive detection various environments such inside living cells, at gigapascal pressure,...
Impurity injection into superfluid helium is a simple and appealing method with diverse applications, including high-precision spectroscopy, quantum computing surface electrons, nano/micromaterial synthesis, flow visualization. Quantized vortices play major role in the interaction between light impurities. However, basic principle governing this still unclear for dense (high mass density refractive index) materials, such as semiconductor metal Here, we provide experimental evidence of...
After 16 years of on-sky operation, Subaru Telescope's facility adaptive optics AO188 is getting several major upgrades to become the extreme-AO AO3000 (3000 actuators in pupil compared 188 previously). will provide high-Strehl images for instruments from visible mid-infrared, notably Infrared Camera and Spectrograph (IRCS), Coronagraphic Extreme Adaptive Optics (SCExAO). For this upgrade, original 188-element deformable mirror (DM) be replaced with ALPAO's 64 × DM. The wavefront sensor also...
We investigate the waveguiding properties of a planar metamaterial slab using terahertz time-domain attenuated total reflection spectroscopy. The enhancement evanescent waves is observed for transverse electric and magnetic excitation caused by resonant waveguide modes in slab. Our calculation describes experimental results justifies extremely small effective thickness. also studied dispersion relations theoretical calculation.
We demonstrated an achromatic wave plate based on parallel metal waveguides in the high THz frequency region. The plates have periodic rough structures surface, which allow slow transverse magnetic propagation and fast electric propagation. A numerical simulation showed that height of roughness is important for optimizing birefringence. fabricated stacked containing two types by chemical etching. An array small pillars allows higher optimization. experimentally quarter-wave region from 2.0...
We demonstrate the optical levitation or trapping in helium gas of a single quantum dot (QD) within liquid droplet. Bright photon emission from levitated QD droplet was observed for more than 200 s. The count rates are consistent with value theoretically estimated two-photon-action cross section. This paper presents realization an optically solid-state emitter. published Optics Letters and is made available as electronic reprint permission OSA. can be found at following URL on OSA website:...
ZnO microspheres fabricated via laser ablation in superfluid helium were found to have bubble-like voids. Even a microsphere demonstrating clear whispering gallery mode resonances the luminescence had Our analysis confirmed that voids are located away from surface and negligible or little effect on since electromagnetic energy localizes near of these microspheres. The existence indicates gas any evaporated target material was present within molten microparticles during formation.
Direct detection and spectroscopy of exoplanets requires high contrast imaging. For habitable in particular, located at small angular separation from the host star, it is crucial to employ inner working angle (IWA) coronagraphs that efficiently suppress starlight. These coronagraphs, turn, require careful control wavefront which directly impacts their performance. ground-based telescopes, atmospheric refraction also an important factor, since results a smearing PSF, can no longer be...
Abstract Nanodiamonds that contain germanium-vacancy centers (GeV-NDs) exhibit significant potential for biomedical and quantum science applications. GeV-NDs with an average particle size of 9 nm were recently fabricated through a detonation process enables the practical-scale production NDs (DNDs). However, optical properties GeV in DNDs have not been studied thoroughly. In particular, luminescence spectrum these GeV-DNDs had unassigned peak at 1.98 eV. Here, we investigate under various...
Soft X-ray angle-resolved photoemission has been performed for metallic V2O3. By combining a microfocus beam (40 µm × 65 µm) and micro-positioning techniques with long-working-distance microscope, it possible to observe band dispersions from tiny cleavage surfaces typical size of several tens µm. The spectra show clear position dependence, reflecting the morphology cleaved sample surface. selecting high-quality flat regions on surface, perform mapping using both photon-energy polar-angle...
ULTIMATE-Subaru is a next facility instrumentation program of the Subaru Telescope. The goal this project to extend wide-field capability near-infrared (NIR), by developing ground-layer adaptive optics (GLAO) system and NIR instruments. GLAO will uniformly improve image quality up 20-arcmin field view in diameter correcting for turbulence. expected after correction FWHM~0".2 K-band under moderate seeing conditions. In presentation, we present preliminary design overview at Cassegrain focus,...
We succeeded in fabricating ZnO microspheres with high sphericity by laser ablation superfluid helium. Such enable efficient lasing the whole visible region due to defects a CW at room temperature. The threshold is found be around 100 W/cm<sup>2</sup>. This value much smaller than those of recent reports on microwire. Cathodoluminescence single was also measured.
We demonstrated the tuning of whispering gallery modes (WGMs) a silica microsphere during optical levitation through annealing process. determined temperature from power balance between CO2 laser light heating and several cooling processes. Cooling caused by heat conduction surrounding air molecules is dominant achieved blueshift WGMs as large 7 nm at 660 covering 40% free spectral range, which was observed in white-light scattering spectrum levitated microsphere.
The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is a high-contrast imaging system installed at the 8-m Telescope on Maunakea, Hawaii. Due to its unique evolving design, SCExAO both an open for use by international scientific community, and testbed validating new technologies, which are critical future imagers Giant Segmented Mirror Telescopes (GSMTs). Through multiple collaborations over years, was able test most advanced technologies in wavefront sensors, real-time...