The method of variational cumulant expansion (VCE) on the Ising model is applied to investigate phase transitions in magnetic alloy nano-particles, which a random site distribution component atoms assumed. By introducing effect exchange constant, it shown numerically that nano-particles can be treated same way as bulk materials. Curie temperature and Néel binary with cubic lattices are calculated. It found both decrease decreasing size nano-particle. Phase diagrams investigated for variable...

Abstract Terahertz (THz) spectroscopic sensing and imaging has identified its potentials in a number of areas such as standoff security screening at portals, explosive detection battle fields, bio-medical research so on. With these needs, the development an intense broadband THz source been focus research. In this work, we report (~10 mW) ultra-broadband (~150 THz) to infrared (IR) with Gaussian wavefront, emitted from nano-pore-structured metallic thin films femtosecond laser pulse...

The process of the light passing through a single subwavelength metal slit is analyzed by finite-difference time-domain method. simulation results show that can be considered as an effective dielectric region sandwiched two scattering regions at ends. Thus, analogous to Fabry-Perot (FP) etalon consisting slab with high-reflection coatings on its surfaces. A formula presented evaluate phase shift caused amplitude transmissivity coatings.

Abstract The continuous photon Hall effect excited in a surface plasmon polariton system is proposed and realized theoretically, which the parallel incident light illuminates small ball nearing surface. scattering direction can be continually modulated large range of almost 180 degree by elliptical polarization state light. physical reason displayed intuitively component waves interference principle.

We present the time-domain analysis of extraordinary optical transmission slits milled on thin metallic film. employ finite-difference method to study variations energies with sampling time received by several monitors that are placed specified positions in structure. It is found physical origin related phenomenon may be contributed a combining effect single-slit and interslits effect. The brought excitation surface-plasmon polaritons from isolated slit caused phase interference transmitted...

We investigate the properties of guide modes localized at interfaces photonic crystal (PC) heterostructures which are composed two semi-infinite two-dimensional PCs consisting non-circular air cylinders with different rotating angles embedded in a homogeneous host dielectric. Photonic band gap structures calculated use plane-wave expansion method combination supercell technique. consider various configurations, for instance, rectangular (square) lattice–rectangular cylinders, and lattices on...

An excellent unidirectional transmission device is proposed, which consists of a two-dimensional photonic crystal and dielectric grating. The designed to have Dirac cone at the Γ point allows normal incident light transmit while reflecting oblique incidence in broad frequency band. aim grating diffract into other directions. Thus, when first passes through then incidents upon crystal, it will be blocked completely. While sequence reversed transmitted. This selectivity makes crystal/grating...

The spontaneous emission rate of an atom in dielectric slabs is shown to exhibit multiperiodic oscillations when the system scale varied. These are calculated using quantum electrodynamics and analyzed ideas from closed-orbit theory. extracted frequencies rates by Fourier transform agree well with actions short photon closed orbits. interpreted as interferences emitted propagating on orbits leaving returning emitting atom. This study provides a new understanding process for atoms presence...

Abstract The magnetic properties of ferromagnetic (FM) single‐layered nanobelts are investigated if there exists a single‐ion anisotropy. quantities as functions belt width and temperature calculated. spontaneous magnetization, area the hysteresis loop, energy level extension increase with width, decrease temperature. Curie increases width. spectra When is fixed, higher leads to lower spectra. spin‐wave energy, well extension, drops rising, becomes zero reaches results compared those FM...

We introduce a method to obtain and describe the multiple defect modes in photonic quantum-well structure [(AB)mC]n(AB)m. It is found that relationship between structural parameters can be obtained by analytically solving dispersion for crystal with its periodic unit [(AB)mC], laconic unifying expression used energy levels of both interface modes. The internal mechanism determine related revealed. believe these findings provide direct guidance practical application.

Photonic skyrmions have been a hot topic in recent years. However, modulating the spin distributions of is still challenging topic. In this paper, we investigate detailed photonic thin metal film sandwiched by different dielectrics. We find that ratios components can be adjusted thickness film, while absolute value total controlled frequency light source. Therefore, choosing proper preparation process and certain beam actual experiment, get exact type distribution prefer. addition, when...

We propose a combination structure which consists of subwavelength metal slit filled periodically with two different dielectrics to modulate plasmon polaritons (slit-PPs). The transmission spectra are simulated by the finite-difference time-domain method and photonic band gaps observed. theoretical formula calculate band-gap structures is deduced calculation results agree satisfactorily results. This can be termed as slit-PP crystal.

Abstract The discovery of Photonic spin Hall effect (PSHE) on surface plasmon polaritons (SPPs) is an important progress in photonics. In this paper, a method realizing multi-channel PSHE two-dimensional metal-air-metal waveguide proposed. By modulating the phase difference $$\phi$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>ϕ</mml:mi> </mml:math> and polar angle $$\theta$$ <mml:mi>θ</mml:mi> dipole source, SPP can propagate along specific channel. We further prove...

The spontaneous emission rate of an atom in a dielectric system with single interface is calculated using quantum electrodynamics and analyzed ideas from closed-orbit theory. shown to exhibit damping oscillation as the atomic distance varied. frequency matches very well prediction This study provides different perspective on atoms presence environments.

We propose a dressed subwavelength metal slit structure, which is formed by adding thin metallic grating near the entrance with distance. The simulation computation means of finite-difference time-domain method shows that transmissivity can be substantially enhanced 30 times compared conventional structure. transmission spectrum exhibits two characters Fabry-Perot resonance and left-shift. introduced has effects: (1) more energy collected from incident plane, (2) effective dielectric region...

In this paper, we applied the band structure theory to investigate plasmonic (PB) structures and optical properties of subwavelength metal/dielectric/metal Bragg waveguides in near infrared range with either dielectric or geometric modulation. The Bloch wave vector, density states, slowdown factor, propagation length transmittance are calculated analyzed. Both modulations favor manipulating surface-plasmon-polariton (SPP) waves. For modulation, PB is mainly formed by SPP modes possesses a...

Using Green's function method, we investigate ferromagnetic films with a simple cubic lattice containing up to ten monolayers. The Hamiltonian includes the Heisenberg exchange term, surface anisotropy (SA) and dipole interaction (DI). We calculate magnetization as of temperature film thickness analyse behaviour spin canting. result is in agreement experiments. phase diagrams SA versus DI show conditions under which spontaneous can occur. As special case, discuss model without DI.

Based on the density functional theory calculations， diffusion of oxygen atoms near Zr（0001）surface is studied by using nudged elastic band method. Firstly， active energy from surface face-centred cubic （SFCC） sites into hexagonal close-packed in Zr（0001） calculated. The for 0.77 eV. Secondly， SFCC octahedral interstitial between second and third layers Octa（2，3） via first Octa（1，2） calculated too. There are two barriers atom to overcome. energies 2.14 2.57 eV， respectively. As a result，...

Abstract The finding of Photon Hall effect (PHE) on metal surface is an important progress in photonics, but it will be more practical if PHE can realized line-type waveguide. In this paper, we suggested a way to realize two-dimensional photonic crystal (PC) Numerical simulation results show that the propagating direction and strength light PC waveguide controlled by polarization state incident light. Different from surface, driven not only circularly polarized light, also linearly...

In this paper we study the extraordinary optical transmission of one-dimensional multi-slits in an ideal metal film. The transmissivity is calculated as a function various structural parameters. oscillates, with period being just light wavelength, spacing between slits. As number slits increases, varies one three ways. It can increase, attenuate, or remain basically unchanged, depending on Each way oscillatory manner. slit interaction responsible for oscillating strength that depends subject...

A new structure of negative-refractive-index material is proposed, which composed ferromagnetic wires setting in two-dimensional Bravais lattice (FWL) with the application external magnetic field. The refractive index FWL consisting ferrum arranged square calculated. exhibits negative value GHz region. notable characteristic that tunable by applied

We use the transfer-matrix method to research band structures in one-dimensional photonic crystals composed of anomalous dispersion material (saturated atomic cesium vapor). Our calculations show that type crystal possesses an ultra-narrow gap and this is tunable when altering electron population ground state by optical pumping method.