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The paper presents the results of investigation of the thermochemical laser-induced periodic surface structures (TLIPSS) formation on metalls film (Ti, Ni, Cr) at femtosecond irradiation with different spot sizes, pulse powers, polarization directions. Also the results of selective TLIPSS etching for transfer a topology of TLIPSS into metal underlayer are presented.
Brillouin dynamic gratings (BDGs) has been, in recent years, addressed using a polarization-maintaining fiber with many prominent advantages and proved that the BDGs have a profound high sensitivity to fiber birefringence changes. When the two parallel polarized counter-propagating pump waves with a frequency offset of fiber Brillouin frequency shift, and the orthogonally polarized probe pulse wave...
High-resolution measurement of refractive index has a wide range of application and employment of the plasmon resonance absorption combined with phase detection is a promising way to achieve 8-digit resolution. However, because the phase detection in light-wave frequency is not simple, we would like to report on a method of refractive-index measurement by using efficiency-alone interrogation. The...
We investigate plasmon excitation on the surfaces of a thin metal-film grating, which are sinusoidally modulated with a common period and different initial phases. Employing Yasuura's method of modal expansion, we numerically find the resonance angle, field distribution, power flow in the vicinity of the grating surfaces, and efficiency of propagating orders. By setting the amplitude of the metal-film...
Recently, much attention has been focused on the vortex electromagnetic (EM) beam, which carries orbital angular momentum (OAM), at radio and radar frequencies. In this paper, radiation pattern synthesis methods for the generation of vortex EM beam based on uniform circular array (UCA) are proposed. Directional elements and concentric-ring arrays are effectively exploited to optimize the radiation...
The band-pass FSS radome can efficiently reduce the radar cross section (RCS) of the antenna because of its excellent transmission characteristics, i.e., flat top and sharp fall-off, which is especially applicable for stealth antenna technology. Due to the transmission advantage of the hexagon loop, the simulation software of Ansoft HFSS based on the Finite element method (FEM) is employed for the...
Interaction of light with the metallic nanostructures gives rise to various novel effects in photonics and optoelectronics [1]. Research of surface plasmons and their excitation by light is of particular interest in the studies of metamaterials, optical antennas, plasmonic sensors, and plasmonic crystals. The enhanced surface plasmon resonance in noble metallic systems at optical frequencies is expected...
Similar to other physical dimensions of light such as amplitude, phase, frequency, time and polarization, orbital angular momentum (OAM), which refers to the spatial structure of light (a spiral wavefront), is an additional degree of freedom to modulate or multiplex information in optical communication systems [1, 2]. Theoretically, OAM and linear-polarization (LP) modes in few mode fibers (FMFs)...
A plane wave incident on a periodic grating is scattered only in discrete directions and the scattered wave is expressed as a sum of diffracted plane waves. Many methods to calculate the amplitudes of the diffracted plane waves have been proposed [1]. At low grazing angle limit of incidence high order diffracted waves disappear and only the zero order diffracted wave with a diffraction amplitude of...
We present a way to observe Spin Hall effect in subwavelength gratings. A spinning evanescent wave can be asymmetrically transformed into propagation waves through one certain diffraction order by a periodical subwavelength grating. By detecting diffraction field distribution behind the grating, we observed spin-dependent diffraction patterns. Furthermore, replacing the periodical grating by a Fibonacci...
We present a grating assisted tunneling scheme for creating tunable synthetic magnetic fields in optically induced one- and two-dimensional (dielectric) photonic lattices [1]. As a signature of the synthetic magnetic fields, we present conical diffraction patterns in lattices with Dirac points in k-space. We compare the light propagation in these realistic (continuous) systems with the evolution in...
Metamaterialsare electromagnetic composites constructed by subwavelength sized microstructures, and thus can exhibit tailored effective permittivity and permeability. Effective-medium theory (EMT) plays a crucial role since it serves as a bridge to link theories, which are frequently conducted on model hypothetical systems, and experiments which are always performed on realistic metamaterial systems...
Cylindrical vector beams (CVBs) have been widely used in many applications, such as optical tweezers, surface plasmon resonance and material processing, because of its symmetric intensity and polarization. Few-mode fiber grating (FMFG) as the high order mode selector has the advantages of high-efficiency, low cost and all-fiber structure. We demonstrate cylindrical vector pulse generation from a mode-locked...
Floquet-Bloch Theory is one of the most rigorous numerical methods to analyze the properties of grating structures. By using Floquet-Bloch theory, the electric and magnetic fields are assumed to consist of an infinite number of space harmonics when an electromagnetic wave propagates in periodic structure of a dielectric waveguide. If a space harmonic is in the fast wave region of the dispersion relationship,...
In this talk, we will introduce a metallic grating structure with gradient index materials to obtain nearly total omnidirectional reflection, regardless of the polarization of incident wave and the impedance properties of the filled materials inside the grating. In addition, as the reflection phase between TE and TM wave impinging on the metallic grating structure is different, the proposed structure...
This paper discusses the amplification of surface plasmons (SPs) via propagation through one or two optically-pumped dipolar gain materials incorporated into the claddings adjacent to a thin metal plane or stripe. Then, cavity designs to ensure single-mode SP lasing are discussed, emphasizing distributed feedback (DFB) concepts. Single-mode DFB lasers are then implemented as a step-in-width metal...
Conventional photodetectors are mostly propelled by p-n junctions, where the detection wavelength is constrained by the bandgap of semiconductor material. Recently, a meta-linsulator-metal (MIM) configuration is demonstrated to be a promising candidate for the next generation photodetection due to its highly tunable operation wavelength, simple configuration, and possibly low cost. The MIM photodetector...
In this work, we investigated near-perfect light absorption in a 2D subwavelength period nanotrench granting fabricated on a gold metal surface. Optical reflectivity spectra from the device were measured at different angles of incidence for TE and TM polarizations, respectively. Near perfect light absorption was observed at different wavelengths at oblique angles of incidence for two polarizations...
Terahertz (THz) spectral band, from about 0.1 to 15 THz, is one of the least explored yet most technologically transformative spectral regions. A large number of interesting scientific phenomena are only accessible by THz photons and THz radiation also finds a lot of practical applications. However, for a long time, THz scientific research and technological development is greatly limited due to the...
A method to integrate the spectroscopic system of the push-broom scanning imaging spectrometer onto a single chip is proposed using echelle diffraction grating to split the light in the near infrared range according to different wavelengths. The on-chip spectrometer consists of an optical on-off switch array, a multi-input echelle diffraction grating (EDG) and a detector array. The designed EDG has...
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