Spectral properties of a one-dimensional photonic crystal with a resonant defect nanocomposite layer

The spectral properties of a one-dimensional photonic crystal with a defect nanocomposite layer that consists of metallic nanoballs distributed in a transparent matrix and is characterized by an effective resonance permittivity are studied. The problem of calculating the transmission, reflection, and absorption spectra of p-polarized waves in such structures is solved for oblique incidence of light, and the spectral manifestation of defect-mode splitting as a function of the volume fraction of nanoballs and the structural parameters is studied. The splitting is found to depend substantially on the nanoball concentration in the defect, the defect layer thickness, and the angle of incidence. The angle of incidence is found at which the resonance frequency of the nanocomposite is located near the edge of the bandgap or falls in the frequency region of a continuous spectrum. The resonance situation appearing in this case results in an additional transmission band or an additional bandgap in the transmission spectrum.     

Spectral properties of a two-dimensional resonant metal-dielectric photonic crystal

We have studied the transmission spectra of resonant two-dimensional photonic crystals of two types, one of which consists of nanocomposite cylinders that form a square lattice in vacuum and the other of which consists of cylindrical holes that form a square lattice in nanocomposite matrix. The nanocomposite consists of metallic nanospheres that are dispersed in a transparent matrix and is characterized by an effective resonant dielectric permittivity. We show that, depending on the position of the resonant frequency of the nanocomposite with respect to the boundaries of the band gap, there arises either an additional transmission band in the transmission spectrum in the band gap or an additional band gap in the continuous spectrum of the photonic crystal. As the structural and geometric parameters of the system change, both the additional transmission band and the additional band gap are considerably modified. We analyze particular features of the spatial distribution of the electromagnetic field intensity in crystals. The considered effects can be used to extend the possibilities of creating new photonic crystals with specified properties.     

Control of absorption spectrum of a one-dimensional resonant photonic crystal

The crystal under consideration is a layered structure consisting of alternating layers of two materials, one of which is a resonantly absorbing gas. It is shown that the combination of the dispersion of an atomic gas with the dispersion of a photonic-bandgap structures allows one to efficiently control the transmission spectra of s- and p-polarized modes in these combined systems. It is found that the spectrum is highly sensitive to the position of the gas resonance frequency with respect to the bandgap edge and to a change in the gas pressure. The transmission, reflection, and absorption spectra of the resonant photonic crystal are studied at an angle of incidence equal to the Brewster angle of a seed photonic crystal. Possible applications of the found particular features of the dispersion of resonant photonic crystals are discussed.     

Spectral properties of one-dimensional photonic crystal with anisotropic defect layer of nanocomposite

The spectral properties of a one-dimensional photonic crystal with a structure defect—anisotropic nanocomposite layer incorporated between two multilayer dielectric mirrors—have been theoretically investigated. Some specific features are revealed in the transmission spectrum of a photonic crystal. They are primarily due to the resonant behavior of the effective permittivity of nanocomposite and the strong dependence of this parameter on the volume fraction of nanoparticles in the composite.     

Defect mode properties in a one-dimensional photonic crystal

Based on the transfer matrix method (TMM), the interaction of electromagnetic waves with one-dimensional (1D) defective photonic crystal in ultraviolet (UV) frequency region had been studied. With the calculated transmittance characteristics in the wavelength domain, it can be found that the defect mode can be generated within the photonic band gap (PBG) at the central wavelength. Also the effects of many parameters such as the angle of incidence, the state of polarization and the defect layer thickness have been taken in account. A significant effect in generating multiple defect peaks within the PBG has been illustrated.     

实现多共振模的一维异质结构光子晶体

用两种正折射率材料设计了一维光子晶体异质结构模型,并利用传输矩阵法对该光子晶体的透射谱进行了理论研究。结果发现:光通过光子晶体时,在较宽的禁带范围内出现透射率为100%的多条共振模,且共振模的数目与光子晶体结构周期数m相对应;当入射角一定时,共振模的位置可以通过介质的折射率、厚度来调制;当入射光入射角度增大时,多共振模出现整体蓝移,同时共振模宽度变窄。这些特性有望应用于多通道窄带滤波器的设计。     

Graphene-based one-dimensional photonic crystal

A novel type of one-dimensional (1D) photonic crystal formed by an array of periodically located stacks of alternating graphene and dielectric stripes embedded into a background dielectric medium is proposed. The wave equation for the electromagnetic wave propagating in such a structure is solved in the framework of the Kronig-Penney model. The frequency band structure of the 1D graphene-based photonic crystal is obtained analytically as a function of the filling factor and the thickness of the dielectric between the graphene stripes. The photonic frequency corresponding to the electromagnetic wave localized by a defect of the photonic crystal formed by an extra dielectric placed in the position of one stack of alternating graphene and dielectric stripes is obtained.     

Transmission properties in a one-dimensional finite extrinsic semiconductor InSb photonic crystal

The properties of wave transmission in a strongly dispersive semiconductor-dielectric photonic crystal (SDPC) are theoretically investigated. We consider a one-dimensional finite SDPC, air/(SD) ^N S/air, where, N is the stack number, S is an extrinsic semiconductor, n-type InSb (n-InSb), and D is a dielectric layer of SiO₂. Transmission peaks can be found in the frequency region where the real part of the complex permittivity of n-InSb is negative. The number of peaks is equal to the stack number N. The positions of peaks can be tuned by the thicknesses of S and D. The peaks are seen to be blue-shifted as the doping density increases, leading to a tunable filter. The locations of peaks are also strongly dependent on the incidence angle, but weakly dependent on the polarization of the incident wave. The results suggest that a tunable multichannel filter can be achieved by using such an SDPC. Filters with tunable and multichannel features are of technical use in photonic applications such as in the optical electronics and communications.     

Optical properties of a periodic one-dimensional semiconductor-organic photonic crystal in UV region

Optical properties of a one-dimensional semiconductor-organic photonic crystal with periodic AlN/3-octylthiophenes (P3OT) multilayer structure are exhibited and confirmed by a calculation of the transfer matrix method (TMM). An AlN/P3OT multilayer structure displays incomplete photonic band gap behavior in the UV region. The AlN/P3OT multilayers with four pairs of 35-nm-AlN and 35-nm-P3OT layers exhibit a high reflectivity of 89% and less absorption of 10% at a wavelength of about 300 nm. These results demonstrate the AlN/P3OT multilayer structure could be a good candidate for absolute inhibition of reflection in the ultraviolet region for a given orientation.     

Omnidirectional reflection from a one-dimensional photonic crystal

We demonstrate that one-dimensional photonic crystal structures (such as multilayer films) can exhibit complete reflection of radiation in a given frequency range for all incident angles and polarizations. We derive a general criterion for this behavior that does not require materials with very large indices. We perform numerical studies that illustrate this effect.     

Omnidirectional reflectance gaps and resonant tunneling effect in a one-dimensional photonic crystal consisting of two metamaterials

We investigate the properties of electromagnetic wave propagating in a one-dimensional photonic crystal (PC) consisting of two metamaterials with different dispersive model. The reflection gaps of metamaterials multilayer system are independent of the incident angle. Not only TE wave but also TM wave, the omnidirectional reflection gaps exhibit the same behavior with different incident angle for metamaterials as double negative material. We also observed that the frequency regimes of zero-transmission bands are different for TE and TM wave with the same incident angle, when one of metamaterials is the permittivity negative (ε < 0) and the other is the double negative. Correspondingly, we show that the result can be act as an efficient polarization splitter. At last, we discuss the resonant tunneling effect. If the total reflection condition is satisfied, the resonant tunneling effect is enhanced as the incident angle increases, even though the propagation wave is evanescent wave in the single layer medium.     

Numerical simulation of nonlinear properties of fullerene-containing one-dimensional photonic crystal

A model of interaction between a one-dimensional photonic crystal (PC) containing a defect (nonlinear optical layer of C₆₀ fullerene) and radiation with a wavelength ??₀= 1064 nm under steady-state conditions has been considered. This structure is a Fabry-Perot microcavity: a fullerene layer (with a thickness multiple of ??₀/2) is placed between the interference mirrors formed by alternating layers ??₀/4 thick. The PC under consideration (1) has a narrow transmission band in the vicinity of ??₀ against the background of a relatively wide 100%-reflection band (photonic band gap) in the linear mode and (2) provides multiple amplification of the radiation intensity in the intermediate layer with respect to the external radiation intensity. Since C₆₀ fullerene exhibits a significant optical Kerr nonlinearity, the optical thickness of the intermediate layer under irradiation deviates from the value multiple of ??₀/2; as a result, 100% transmission for ??₀ changes to almost 100% reflection at a certain radiation intensity. Thus, this structure behaves as a peculiar optical limiter.     

Band structure of a two-dimensional resonant photonic crystal

The band structure of two-dimensional resonant photonic crystals of two types has been calculated using the expansion of eigenfunctions in plane waves. Crystals of one type consist of infinite dielectric cylinders forming a square lattice filled with a resonant gas, and crystals of the other type consist of infinite cylindrical holes filled with a resonant gas and forming a square lattice in a dielectric matrix. It has been shown that, in both cases, the dispersion of a resonant gas in combination with the dispersion of a two-dimensional structure with a photonic band gap leads to the appearance of an additional narrow transmission band near the edge of the band gap or an additional band gap in the continuous spectrum of the photonic crystal. The calculations performed have demonstrated that new dispersion properties substantially depend on the density of the resonant gas, the position of the resonant frequency with respect to the edge of the band gap, and the direction of propagation of electromagnetic waves.     

含特异材料光子晶体隧穿模的偏振特性

构造了由普通材料A(SiO₂)和电单负材料B组成的(AB)^N(BA)^N型一维光子晶体.数值计算表明原禁带的1907.3 nm处出现了一个十分尖锐的隧穿模. 入射角增加,该隧穿模的透射率和半峰全宽度均保持不变,但位置发生蓝移, 入射角在15°-65°的区间内,移动率的绝对值 |dλ/dθ| 较大.当B介质的磁导率μ_B 从5增加到10时,只是隧穿模的位置发生了红移. 介质的几何厚度增加时,隧穿模的透射率不变,但其位置红移明显,半峰全宽略有增加.     

Optical properties of high-order band gaps in one-dimensional photonic crystal

Plane wave expansion method and transfer matrix method have been used to study the optical properties of eighty ninth photonic band gaps (PBGs) in one dimensional photonic crystal (1DPCs) with a form of Si (air|Si)₈. The results show that high order PBGs (HR-PBGs) in normalize dispersion curves have slower convergence speed than low order PBGs (LR-PBGs) and appear periodic detergency phenomena with the increasing of Λ/λ values (where Λ is the constant of one dimensional lattice and λ is wavelength) and their band widths and central wavelengths are more sensitive to fabrication errors than that of LR-PBG. Finally, some special forms of Si (air|Si)₈ structure with input and output rib waveguides are fabricated on Silicon-on-Insulator (SOI) materials by semiconductor micromachining technology. By measuring and analyzing their insertion loss spectra, we demonstrate that the HR-PBGs of 1DPCs also have the potential application in integration optics.     

Model system for a one-dimensional magnetic photonic crystal

We fabricate and characterize one-dimensional magnetic (rather than dielectric) photonic crystals for the first time. Our model system is a one-dimensional periodic lattice of gold-wire pairs. Each pair can be viewed as a magnetic coil with two slits and represents a "magnetic atom." Strong coupling between the resulting magnetic-dipole resonance and the Bragg resonance is accomplished by an adjacent dielectric slab waveguide, giving rise to an avoided crossing at near-infrared wavelengths. Our experimental findings are in excellent agreement with theory.     

1维光子晶体缺陷模

利用光学传输矩阵理论对掺杂1维光子晶体的缺陷模进行了研究。计算和分析了缺陷层折射率、缺陷层厚度与缺陷峰的关系。得出结论：随着缺陷层厚度的增大,缺陷峰波长呈线性增加,但是当缺陷层厚度增加到一定值时,缺陷峰的个数也将不断增加;缺陷层折射率也与缺陷峰波长有线性正比关系。从而提出了一种在微波领域测量介质折射率和介电常数的有效方法。     

1维光子晶体缺陷模

 利用光学传输矩阵理论对掺杂1维光子晶体的缺陷模进行了研究。计算和分析了缺陷层折射率、缺陷层厚度与缺陷峰的关系。得出结论：随着缺陷层厚度的增大,缺陷峰波长呈线性增加,但是当缺陷层厚度增加到一定值时,缺陷峰的个数也将不断增加;缺陷层折射率也与缺陷峰波长有线性正比关系。从而提出了一种在微波领域测量介质折射率和介电常数的有效方法。     

Density of states of a one-dimensional disordered photonic crystal

An analytic theory of the density of states in one-dimensional disordered photonic crystals is proposed. It is shown that the problem of the density of optical modes can be reduced in the small dielectric contrast approximation to solving a generalized Fokker-Planck equation for the distribution function of the logarithmic derivative of the electric field (the wave phase). The exact analytic solution and density-of-states asymptotics deep in the band gap of the photonic crystal and close to the band gap edge are derived. The results obtained agree well with the empirical relations derived earlier from numerical experiments.     

Spectral self-similarity in fractal one-dimensional photonic structures

Transmission spectra of one-dimensional fractal multilayer structures are found to exhibit self-similar properties. Self-similarity manifests itself in the shape of a transmission envelope (map of transmission dips) rather than in the map of resonance transmission peaks, as is commonly the case with spectra of quasiperiodic systems. To observe the self-similarity, one needs to apply a power transformation to the transmittance in addition to the usual frequency scaling. The values of this power as well as the scaling factor have been calculated analytically and found to depend on the geometrical parameters of the structure.