Electromagnetic Metamaterials: Transmission Line Theory and Microwave Applications. By Christophe Caloz and Tatsuo Itoh.

Thermal radiation is one of the most universal physical phenomena, and its study has played a key role in the history of modern physics. Our understanding of this subject has been traditionally bas...

Radiative Heat Transfer

Scattering of electromagnetic waves by subwavelength objects is accompanied by the excitation of electric and magnetic Mie resonances that may modify substantially the scattering intensity and radiation pattern. Scattered fields can be decomposed into electric and magnetic multipoles, and the magnetic multipoles define magnetic response of structured materials underpinning the new field of all-dielectric resonant meta-optics. Here we review the recent developments in meta-optics and nanophotonics and demonstrate that the Mie resonances can play a crucial role offering novel ways for the enhancement of many optical effects near magnetic and electric multipolar resonances, as well as driving a variety of interference phenomena which govern recently discovered novel effects in nanophotonics. We further discuss the frontiers of all-dielectric meta-optics for flexible and advanced control of light with full phase and amplitude engineering, including nonlinear nanophotonics, anapole nanolasers, quantum optics, ...

Functional Meta-Optics and Nanophotonics Govern by Mie Resonances

We report a new type of phononic crystals with topologically nontrivial band gaps for both longitudinal and transverse polarizations, resulting in protected one-way elastic edge waves. In our design, gyroscopic inertial effects are used to break the time-reversal symmetry and realize the phononic analogue of the electronic quantum (anomalous) Hall effect. We investigate the response of both hexagonal and square gyroscopic lattices and observe bulk Chern numbers of 1 and 2, indicating that these structures support single and multimode edge elastic waves immune to backscattering. These robust one-way phononic waveguides could potentially lead to the design of a novel class of surface wave devices that are widely used in electronics, telecommunication, and acoustic imaging.

Topological Phononic Crystals with One-Way Elastic Edge Waves

Provided are a wireless charging system and methodology including a charging station, an application, and a server configured and operating to facilitate wireless vehicle charging. The charging station includes a charging unit for transferring power, a control unit, and a communication unit. The application is accessible through a mobile device and capable of communicating with the charging station. The server is capable of communicating with the charging station and the mobile device.

Systems and mobile application for electric wireless charging stations

Vanadium dioxide (VO2) exhibits a phase-change behavior from the insulating state to the metallic state around 340 K. By using this effect, we experimentally demonstrate a radiative thermal rectifier in the far-field regime with a thin film VO2 deposited on the silicon wafer. A rectification contrast ratio as large as two is accurately obtained by utilizing a one-dimensional steady-state heat flux measurement system. We develop a theoretical model of the thermal rectifier with optical responses of the materials retrieved from the measured mid-infrared reflection spectra, which is cross-checked with experimentally measured heat flux. Furthermore, we tune the operating temperatures by doping the VO2 film with tungsten (W). These results open up prospects in the fields of thermal management and thermal information processing.

Experimental investigation of radiative thermal rectifier using vanadium dioxide

Dynamic control of electromagnetic heat transfer without changing mechanical configuration opens possibilities in intelligent thermal management in nanoscale systems. We confirmed by experiment that the radiative heat transfer is dynamically modulated beyond the blackbody limit. The near-field electromagnetic heat exchange mediated by phonon–polariton is controlled by the metal–insulator transition of tungsten-doped vanadium dioxide. The functionalized heat flux is transferred over an area of 1.6 cm2 across a 370 nm gap, which is maintained by the microfabricated spacers and applied pressure. The uniformity of the gap is validated by optical interferometry, and the measured heat transfer is well modeled as the sum of the radiative and the parasitic conductive components. The presented methodology to form a nanometric gap with functional heat flux paves the way to the smart thermal management in various scenes ranging from highly integrated systems to macroscopic apparatus.

Dynamic Modulation of Radiative Heat Transfer beyond the Blackbody Limit.

A new type of dipole antenna using a left-handed transmission line is proposed. The antenna is composed of a transmission line loaded periodically with shunt inductors and series capacitors. The placement of capacitors into one side only of the line leads to currents of different amplitude on the two sides. Because out-of-phase currents have different amplitudes, they do not completely cancel in the far field, and as a result radiate. Numerical investigation of a wire model shows a unique feature of left-handed transmission lines, which is a reduced wavelength with decreasing frequency. Measured results of two antennas are presented. One is a short dipole antenna working at n=-1, based on conventional resonance numbering. The antenna of 0.18 wavelengths in free space has a gain of -3.9 dBi and bandwidth of 1.7% for |S11 |<-10 dB. The other is a meandered dipole antenna working at n=-9. Polarization orthogonal to a right-handed one is achieved by the induced current of |-9| half wavelengths on the meander having 0.77 wavelengths in free space

Left-Handed Dipole Antennas and Their Implementations

Here, we show analytically that the thermal rectification via evanescent waves is obtained in the parallel semi-infinite bodies of the dielectric-coated silicon carbide and uncoated silicon carbide. The permittivity and the thickness of the dielectric coating are derived for maximizing the thermal rectification. In the nonequilibrium situation holding temperatures of 500 K for one body and 300 K for the other, either a coating with a high permittivity of 14 and a thickness of 1 nm or a coating with a low permittivity of 2 and a thickness exceeding 10 nm, results in rectifying coefficients of 0.4 to 0.44.

/pdf/rectification-of-evanescent-heat-transfer-between-dielectric-2xfanpwy1w.pdf

Rectification of evanescent heat transfer between dielectric-coated and uncoated silicon carbide plates

In this paper, the authors propose a new type of microstrip line to waveguide transition that is fabricated on a single layer dielectric substrate. By controlling the size of a matching element and the length of an inserted microstrip line across a waveguide, impedance matching of the transition can be achieved.

/pdf/millimeter-wave-microstrip-line-to-waveguide-transition-19s0c3jikk.pdf

Hideo Iizuka

Papers

Experimental investigation of radiative thermal rectifier using vanadium dioxide

Dynamic Modulation of Radiative Heat Transfer beyond the Blackbody Limit.

Left-Handed Dipole Antennas and Their Implementations

Rectification of evanescent heat transfer between dielectric-coated and uncoated silicon carbide plates

Millimeter-wave microstrip line to waveguide transition fabricated on a single layer dielectric substrate