Search

The optical transmission properties of metal-dielectric multilayer gratings have been investigated both experimentally and numerically. A remarkable transmission resonance, which makes a significant difference from that of traditional single/triple-layer analogs, has been reported. To understand its physical origin, a field-interference mechanism of dipole arrays induced by the lateral and vertical plasmon coupling has been suggested.

We have fabricated a metamaterial of metal/semiconductor/metal sandwich nanostrips structure comprising a pair of gold strips and a vanadium dioxide (VO2) strip. The optical response of the metamaterial has been studied. The results indicate the nanostructure with VO2 strips can be used as a temperature-controlling optical switch and the mechanism of this switch can be explained by the magnetic resonance.

We report the observation of enhanced optical transmission through the metal subwavelength hole arrays with nanoparticle inside the hole, and demonstrate the transmission enhancement and the suppression due to the excitation of the localized surface plasmon (LSP). We interpret this phenomenon with the Fano theory considering the real and imaginary parts of the polarizability of the LSP.

Polarized optical transmission properties through the L-shaped holes array in silver film was investigated at near infrared wavelength. Besides the enhanced transmission due to the combined plasmonic excitations, strong optical rotation was definitely observed at specific polarized incidences. After elaborate analyses, two eigenmodes were clearly characterized as the results of the hybrid localized plasmon resonances. Any polarization states from the incidences will degenerate into these two eigenstates after transmissions, suggesting a practical method to manipulate the polarization of light. Our result demonstrates the giant rotation rate achieved by the nanothin sample, indicating potential applications in the micro-optical devices.

The optical transmission spectra of structured metal films, which were fabricated by depositing a thin metal layer on the perforated metal surface, have been experimentally studied in this paper. They exhibit an extraordinary cutoff effect at certain wavelength, beyond which no efficient light transmission can be achieved. A systematic study reveals that the cutoff wavelength is dependent on the lattice period but not on the hole shape or size, making a difference to the cutoff of waveguide. To understand the effect, a qualitative explanation has been proposed.

A systematic theoretical study is presented for the electronic, mechanical, and optical properties of cubic Ti3N4, Zr3N4, and Hf3N4 with the Th3P4 structure in the framework of density functional theory. The calculated band structures of Ti3N4, Zr3N4, and Hf3N4 show the indirect band gaps of 0.268, 0.909, and 1.00eV, respectively. Furthermore, the optical properties for all three materials were calculated and analyzed in detail. The calculated results are well consistent with available experimental data. Also, it is shown that all these materials have relatively large static dielectric constants at zero frequency, rendering them potential applications in microelectronic devices.

Recent experiments indicated that disorder effect in DNA may lead to a transition of the charge transport mechanism from band resonant tunnelling to thermal activated hopping. In this letter, based on Mott's variable-range hopping theory we present a kinetic study for the charge transport properties of DNA molecules. Beyond the conventional argument in large-scale systems, our numerical study for finite-size DNA molecules reveals a number of unique features for (i) the I-V characteristics, (ii) the temperature and length dependence, and (iii) the transition from conducting to insulating behaviors.