Junichi Takahara 교수

The concept of a one-dimensional optical wave and its waveguides are proposed for what is to our knowledge the first time. The proposed waveguides are principally new and named for one-dimensional optical waveguides. One-dimensional optical waveguides make it possible to guide very thin optical beams in the visible or the near-infrared region with a diameter in the nanometer range. The propagation properties are analyzed theoretically. The applications of the waveguides to optical devices in the

Abstract Benefited from the well‐known Mie resonance, a plethora of physical phenomena and applications are attracting attention in current research on dielectric‐based nanophotonics. High‐index dielectric metastructures are favorable to enhance light‐matter interaction in nanoscale with advantages such as low loss, optical magnetism, and multipolar responses, which are superior to their plasmonic counterpart. In this review, we highlight the important role played by Mie resonance‐based multipol

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text Junichi Takahara and Tetsuro Kobayashi, "Low-Dimensional Optical Waves And Nano-Optical Circuits," Optics & Photonics News 15(10), 54-59 (2004) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

All-dielectric color printing by means of high-index Mie resonators has enabled wider control of reflection colors depending on structural geometry. However, modifying the geometry, including the height, by using conventional fabrication processes remains challenging, and drastic color modification approaches via the addition of a new tuning axis are required to extend color varieties and applications. Here, we demonstrate all-dielectric pixel color control through Si oxidation. Oxidized monocry

Mie resonance wavelengths of a dielectric structure are strongly dependent on the inherent material property and structural geometry. In particular, a high-index nanostructure enables light confinement within itself over the range of visible wavelengths, which allows the Mie resonator to be applied to a pixel in color printing of subwavelength-scale resolution. However, if the Mie resonator is packed into a smaller area in order to achieve better resolution, the interaction between adjacent reso

In this paper, we theoretically and experimentally demonstrated photothermal nonlinearities of both forward and backward scattering intensities from quasi-perfect absorbing silicon-based metasurface with only <i>λ</i>/7 thickness. The metasurface is efficiently heated up by photothermal effect under laser irradiation, which in turn modulates the scattering spectra via thermo-optical effect. Under a few milliwatt continuous-wave excitation at the resonance wavelength of the metasurface, backward

In order to investigate anisotropic transport in various types of lattices, two-dimensional electron gas in the hexagonal and rectangular antidot lattices are measured. Magnetoresistance is isotropic in hexagonal lattice, but anisotropic in the rectangular lattice with circular antidots. The influence of antidot shapes upon anisotropic transport is also investigated in the rectangular lattice. It is found that the anisotropic transport is sensitive to the arrangement and the shape of antidot pot

A symmetric metal slab waveguide simultaneously supports two opposite types of propagation mode similar to a metal film: short-range surface plasmon (SRSP) like mode and long-range surface plasmon (LRSP) like mode. The strong field confinement of SRSP-like mode plays a crucial role for nano-optical integrated circuits in spite of short propagation length. In order to avoid the trade-off between field confinement and propagation length, we demonstrate selective mode excitation and mutual mode con

The canonical studies on Mie scattering unravel strong electric/magnetic optical responses in nanostructures, laying foundation for emerging meta-photonic applications. Conventionally, the morphology-sensitive resonances hinge on the normalized frequency, i.e. particle size over wavelength, but non-paraxial incidence symmetry is overlooked. Here, through confocal reflection microscopy with a tight focus scanning over silicon nanostructures, the scattering point spread functions unveil distinctiv

A thermal radiation light source, such as an incandescent light bulb, is considered a legacy light source with low luminous efficacy. However, it is an ideal energy source converting light with high efficiency from electric power to radiative power. In this work, we evaluate a thermal radiation light source and propose a new type of filament using a refractory metasurface to fabricate an efficient light bulb. We demonstrate visible-light spectral control using a refractory metasurface made of ta

Metal optical waveguides and the applications to nano-optical circuits are studied. The concept of "low-dimensional optical waves" is introduced for simplicity. Propagation modes of slab and cylindrical waveguides are analyzed theoretically.

Adaptive pixel operating in the infrared region enables the encoding of invisible information and extraction using specific inputs. Recently, the formation of an adoptive image by utilizing VO2 having the property of phase transitions has been demonstrated. However, the improvement of its pixel resolution is challenging, and a simple geometry is needed to ensure accuracy and reproducibility of the optical function of the pixel; therefore, the proposal of a different working principle is required