Coiling-Up Space Metasurface for High-Efficient and Wide-angle Acoustic Wavefront Steering

The recent advent of acoustic metasurface displays tremendous potential with their unique and flexible capabilities of wavefront manipulations. In this paper, we propose an acoustic metagrating made of binary coiling-up space structures to coherently control the acoustic wavefront steering. The acoustic wave steering is based on the in-plane coherent modulation of waves in different diffraction channels. The acoustic metagrating structure with a subwavelength thickness is realized with 3D printed two coiling-up space metaunits. By adjusting structural parameters of the metaunits, the −1st-order diffraction mode can be retained, and the rest of the diffraction orders are eliminated as much as possible through destructive interference, forming a high-efficiency anomalous reflection in the scattering field. The anomalous reflection performance of the designed metagrating is achieved over a wide range of incident angles with high efficiency.

A dual-band polarization insensitive metamaterial absorber with a single metal square patch for sensing application

We proposed a dual-band polarization-insensitive metamaterial absorber consisting of merely the metal square patch and a continuous metal ground separated by a middle dielectric layer. Two resonance peaks derived from `the fundamental resonance (with 97% absorbance) and the surface lattice resonance (with 99% absorbance) are realized. It is different from previous work the dual-band response is obtained by combining two resonances of different sizes. Moreover, a first-order diffraction mode of grating predicted the resonance wavelength of the proposed absorber. The surface electromagnetic field distributions of the unit-cell structure reveal the physical origin of the dual-band absorption. Importantly, the first absorption peak result from surface lattice resonance with narrow line-width has large sensitivity perform and high quality factor, which has significant potential in the application of biosensors and monitoring.

A Dual-band Polarization Insensitive Metamaterial Absorber With a Single Metal Square Patch for Sensing Application

We proposed a dual-band polarization-insensitive metamaterial absorber consisting of merely the metal square patch and a continuous metal ground separated by a middle dielectric layer. Two resonance peaks derived from `the fundamental resonance (with 97% absorbance) and the surface lattice resonance (with 99% absorbance) are realized. It is different from previous work the dual-band response is obtained by combining two resonances of different sizes. Moreover, a first-order diffraction mode of grating predicted the resonance wavelength of the proposed absorber. The surface electromagnetic field distributions of the unit-cell structure reveal the physical origin of the dual-band absorption. Importantly, the first absorption peak result from surface lattice resonance with narrow line-width has large sensitivity perform and high quality factor, which has significant potential in the application of biosensors and monitoring.

Формирование интерметаллида Cu-=SUB=-6-=/SUB=-Sn-=SUB=-5-=/SUB=- в тонких пленках Cu/Sn

The study of the formation of the Cu6Sn5 intermetallic compound in Sn(55nm)/Cu(30nm) thin bilayer films was carried out directly in the column of a transmission electron microscope (electron diffraction mode) by heating the film sample from room temperature to 300 °C and recording the electron diffraction patterns. The thin films formed as a result of a solid state reaction were monophase and consisted of the η-Cu6Sn5 hexagonal phase. The temperature range for the formation of the η-Cu6Sn5 phase was determined. The estimate of the effective interdiffusion coefficient of the reaction suggests that the main mechanism for the formation of the Cu6Sn5 intermetallic is diffusion along the grain boundaries and dislocations.

Акустооптическое управление энергетическим 2D-профилем лазерного луча

The acousto-optic control of the energy profile of laser radiation is considered. A highly efficient multibeam Bragg diffraction mode with a combination of beams close in angular space, forming an averaged pattern in the form of a single beam, is used. In this case, the two-dimensional intensity profile is realized as a product of two independent one-dimensional profiles. On the basis of a polarization-independent two-coordinate acousto-optic deflector, several profiles (including a close to uniform one) were experimentally obtained with a total efficiency of no less than 85% and a profile change time of about ten microseconds. This method can be used in systems for processing materials with powerful lasers.

A Polarization-insensitive Dual-band Plasmonic Metamaterial Absorber for a Sensor Application

A polarization-insensitive dual-band plasmonic metamaterial absorber is proposed, which is constituted by merely the metal nano-cylinder and a continuous metallic ground separated by a middle dielectric layer. Two resonance peaks with over 99% absorbance derived from `the fundamental resonance and the surface lattice resonance are realized. In addition, we demonstrated that proposed dual-absorber retain nearly perfect absorbance for all polarization angles of both TE and TM modes on normal incidence. It is different from previous work that the dual-frequency response is obtained by combining two subunits of different sizes. Moreover, a first-order diffraction mode of grating predicted the resonance frequency of the proposed absorber. Importantly, the second absorption peak result from surface lattice resonance with narrow line-width has large sensitivity perform and high quality factor, which has significant potential in the application of biosensors and monitoring.

Дифракционная селекция мод в гетеролазерах с планарными брэгговскими структурами

Within the coupled waves method complemented by quasi-optical approach, we investigate a possibility of diffraction mode selection with respect to the transverse mode index in lasers with planar Bragg resonators. Allowable values of the Fresnel parameter are determined which provide for establishment of stationary single-mode oscillation regime with narrow angle spectrum due to diffraction losses from the edges of the Bragg structure. We show that at larger values of the Fresnel parameter, oscillation stability can be improved by shifting the operating transition frequency to the eigenfrequency of the highest-Q longitudinal mode of the Bragg resonator.