Resonant modes in quantum well structure of photonic crystals with different lattice constants

The resonant modes in a quantum well (QW) structure composed of three slabs of two dimensional (2D) photonic crystals with different lattice constants are analyzed with plane-wave-based transfer matrix method (TMM). It is found that the energy band of the well slab submerged into the band gap of barrier slab is discretized into quantized modes and the number of the resonant modes changes with the well slab thickness. A model structure of asymmetrical photonic QW consisting of two slabs of 2D photonic crystals with different lattice constants and one uniform dielectric slab in between is proposed and the resonant modes in it are investigated with the same method. A useful numerical simulation method for theoretical discussion as well as for practical application about photonic QW structure of photonic crystals with different lattice constants is proposed.     

不同晶格常数光子晶体构成的光量子阱中的共振模

用基于平面波的传输矩阵法分析由具有不同晶格常数的光子晶体材料构成的光量子阱结构中的共振模，发现湮没于垒层的阱层能带分离成共振模，且共振模的数目随阱层的厚度变化而改变。提出一种新型的非对称量子阱结构模型，由2块晶格常数不同的光子晶体材料和夹在光子晶体材料中间作为阱层的均匀介电材料构成，并对其中的共振模进行了分析。指出当阱层厚度达到构成垒层的光子晶体晶格常数的一半时出现一个共振模，若继续小量增加阱层厚度将使共振模频率出现红移。最后给出一种基于平面波的传输矩阵法，且对于不同晶格常数的光子晶体量子阱结构均有效的数值模拟方法，可用于研究由三维光子晶体材料或者色散材料组成的光子晶体量子阱结构。     

Controllable Photonic Band Gap and Defect Mode in a 1D CO2-Laser Optical Lattice

We propose a new method to form a novel controfiable photonic crystal with cold atoms and study the photonic band gap （PBG） of an infinite 1D CO2-laser optical lattice of SSRb atoms under the condition of quantum coherence. A significant gap generated near the resonant frequency of the atom is founded and its dependence on physical parameters is also discussed. Using the eigenquation of defect mode, we calculate the defect mode when a defect is introduced into such a lattice. Our study shows that the proposed new method can be used to optically probe optical lattice in situ and to design some novel and controllable photonic crystals.     

The superprism effect using large area 2D-periodic photonic crystal slabs

The “superprism effect” is an effect observed in photonic crystal structures whereby the direction of light propagation is extremely sensitive to the wavelength and angle of incidence. To realize the superprism effect, new structures are presented which rely on the sensitivity of the phase velocity in a two-dimensional (2D) photonic crystal slab to observe angular magnification outside the photonic crystal medium. Constant frequency contour calculations for a photonic crystal slab of finite thickness are used to predict the phase velocity superprism effect. Further analysis using 2D finite-difference time-domain simulations indicate that a large area photonic crystal and wide excitation beam are necessary for clear observation of the superprism effect. A fabrication technique is demonstrated to achieve the structure's required nanometer-sized features over centimeter-scale areas.     

Silicon-based two-dimensional photonic crystal waveguides

A review of the properties of silicon-based two-dimensional (2D) photonic crystals is given, essentially infinite 2D photonic crystals made from macroporous silicon and photonic crystal slabs based on silicon-on-insulator basis. We discuss the bulk photonic crystal properties with particular attention to the light cone and its impact on the band structure. The application for wave guiding is discussed for both material systems, and compared to classical waveguides based on index-guiding. Losses of resonant waveguide modes above the light line are discussed in detail.     

Reconfigurable 3D photonic lattices by optical induction for optical control of beam propagation

We report on our recent theoretical and experimental studies of three-dimensional (3D) photonic lattice structures which are established in a bulk nonlinear crystal by employing different optical induction techniques. These 3D photonic lattices bring about new opportunities for controlling the flow of light via coupling engineering originated from the lattice modulation along the beam propagation direction. By fine tuning the lattice parameters, we observe a host of unusual behaviors of beam propagation in such reconfigurable 3D lattices, including enhanced discrete diffraction, light tunneling inhibition—better known as coherent destruction of tunneling (CDT), anomalous diffraction, negative refraction, as well as CDT-based image transmission. In addition, we propose and demonstrate a new way of creating 3D ionic-type photonic lattices by controlled Talbot effect.     

一维掺杂光子晶体缺陷模的共振理论

为了得到一维掺杂光子晶体的共振理论,建立了一维掺杂光子晶体的谐振腔模型,利用谐振腔的共振条件推导出缺陷模频率满足的解析公式,从理论上解释了产生一维掺杂光子晶体缺陷模的物理机理.利用频率的解析公式对缺陷模的频率随入射角、杂质光学厚度以及杂质折射率的变化规律进行了研究,解释了一维掺杂光子晶体缺陷模的变化规律.与特征矩阵法的计算结果相比,其结果完全吻合,从而证明了共振理论的正确性,弥补了一维光子晶体研究中数值计算方法的不足.     

一维掺杂光子晶体缺陷模的共振理论

为了得到一维掺杂光子晶体的共振理论,建立了一维掺杂光子晶体的谐振腔模型,利用谐振腔的共振条件推导出缺陷模频率满足的解析公式,从理论上解释了产生一维掺杂光子晶体缺陷模的物理机理.利用频率的解析公式对缺陷模的频率随入射角、杂质光学厚度以及杂质折射率的变化规律进行了研究,解释了一维掺杂光子晶体缺陷模的变化规律.与特征矩阵法的计算结果相比,其结果完全吻合,从而证明了共振理论的正确性,弥补了一维光子晶体研究中数值计算方法的不足.     

有效折射率微扰法研究单缺陷光子晶体平板微腔的性质

应用有效折射率微扰法结合二维/三维平面波方法研究了施主和受主缺陷型H1微腔的性质, 使用修正后的有效折射率可以准确地计算微腔的腔模频率, 与三维全矢量时域有限差分法的计算结果很相近. 对于施主型H1微腔, 以介质带边为匹配标准修正的有效折射率计算的微腔腔模频率误差最小, 而对于受主型H1微腔, 匹配标准则应设置为中间带. 有效折射率微扰法既可以将计算的维度从三维降到二维, 大大减少计算所需的计算机内存和时间, 又可以保持计算结果的准确性, 这对于光子晶体微腔的广泛应用具有非常重要的价值.     

Sculpting the vacuum in a photonic band gap micro-chip

We describe the engineering of the electromagnetic vacuum in a 2D–3D photonic bandgap (PBG) hetero-structure. This facilitates the development of novel active devices and the observation of novel quantum electrodynamic phenomena. We consider a specific architecture suitable as an all-optical micro-transistor capable of novel ultra-fast response with low switching power requirements. This relies on a unique collective atomic switching and population inversion achieved by coherent resonant pumping in a suitably engineered vacuum. Specific waveguide architectures within the 3D PBG micro-chip provide local density-of-states (LDOS) peaks near their cutoff frequency. These provide “building blocks” for electromagnetic vacuum engineering without recourse to conventional high Q-factor micro-cavities. For the all-optical micro-transistor, a fork shape LDOS within the micro-chip is desirable, using trimodal waveguide architecture. We delineate the functional robustness of these architectures to disorder caused by manufacturing errors within the PBG micro-chip.     

一种研究一维掺杂光子晶体缺陷模的方法

建立一维掺杂光子晶体的谐振腔模型并研究其缺陷模特性,采用相干叠加的方法推导缺陷模的透射率及频率,建立一种研究缺陷模的方法——相干叠加法.将相干叠加法与特征矩阵法和共振理论进行比较,结果表明:相干叠加法具有特征矩阵法和共振理论的优点,并克服了特征矩阵法和共振理论的不足.相干叠加法是一种研究一维掺杂光子晶体缺陷模的更为有效的方法.     

All-optical switch based on photonic crystal microcavity with multi-resonant modes

We present a design of all-optical switches based on one-dimensional photonic crystals (1D PhC) doped with nonlinear optical materials. The 1D PhC switch structure is composed of a PhC cavity sandwiched by two accessional PhC microcavities. The center PhC cavity has two resonant frequencies with nearly the same quality factors (Q), while the accessional PhC cavities have the same resonant frequency, which is equal to one of the resonant frequencies of the center cavity. The two accessional PhC cavities cause reduction of Q value in this resonant frequency and result in different Q values of two modes. We realize all-optical switch effect by selecting pump light wavelength at the low Q mode and probe light wavelength at the other mode. The theoretical simulations by using the finite difference time domain method show that the pump light intensity required to realize optical switch effect in the designed switch is 50 times smaller than that in one-dimensional photonic crystals cavity with only one resonant mode.     

Investigation on two dimensional photonic crystal resonant cavity based bandpass filter

In this paper, different cavities, namely quasi square, tri-quarter square, square, hexagonal, circular, elliptical, diamond and annular ring based photonic crystal bandpass filters (PCBPFs) are proposed and investigated by exploiting coupling between two in-line quasi waveguides and a resonant cavity. The resonant wavelength, output efficiency and bandwidth of designed PCBPFs are studied by varying the size of the cavity. The normalized transmission spectra of PCBPF are observed using 2D finite difference time domain (FDTD) method. The photonic band gap (PBG) is calculated by plane wave expansion (PWE) method. The circular cavity based PCBPF gives better performance than others because of its circular resonating modes. The number of passbands is increased linearly while increasing the size of the cavity. The overall size of the PCBPF chip is about 11.4 μm × 11.4 μm, which is more suitable for photonic integrated circuits (PIC), wavelength division multiplexing (WDM) systems and sensing applications.     

带多孔硅表面缺陷腔的半无限光子晶体Tamm态及其折射率传感机理

结合表面缺陷半无限光子晶体Tamm态与多孔硅光学传感机理,在光子晶体表面缺陷腔中引入多孔硅,并利用其高效的承载机制,提出基于多孔硅表面缺陷光子晶体Tamm态的折射率传感结构.在半无限光子晶体中缺陷腔与原来的周期性分层介质结构的界面上存在Tamm态,通过入射角度调制使其在缺陷腔中实现多次全反射,并在缺陷腔中加入吸收介质,使谐振波长在缺陷腔中完成衰荡,从而在反射谱中得到缺陷峰;调整光子晶体参数,使缺陷峰的半高全宽得到优化,提高其品质因数(Q值);在此基础上,根据Goos-H?nchen相位移与谐振波长的关系,建立由待测样本折射率改变所导致的多孔硅表面吸附层有效折射率变化与缺陷峰值波长漂移之间的关系模型,并分析其折射率传感特性.结果表明,此生物传感结构Q值为1429,灵敏度为546.67 nm/RIU,证明了该传感结构的有效性,可为高Q值和高灵敏度折射率传感器的设计提供一定的理论参考.     

电磁波在周期介质中的传播及二维光子晶体的光子带结构

光子晶体是光学与凝聚态物理交叉的新领域,也是近年来应用物理学的一个重要研究领域,它是一种由介电常数高的(低的)介质在另一种介电常数低的(高的)背景介质中周期排列所组成的人造多维周期结构材料,能够产生光子带隙。频率落在带隙内的光在晶体里沿任何方向都不能传播,因而具有能够抑制原子、分子的自发辐射等诱人的光电子学特性,在基础研究和实际应用上都有着巨大的潜力。本文在这一领域里进行了富有成效的研究,获得了很好的结果。主要有:(1)利用平面波展开方法来计算二维光子晶体的带隙结构。首先,我们设计正方晶胞的二维光子晶体模型。设x₃方向为介质柱的轴方向,二维周期结构在x₁-x₂平面上。晶胞的晶格常数为a,半径为r,介质柱和空气柱的介电常数分别为ε_a=17和ε_b=1,a>2r。设计的核心思想是通过降低光子晶体结构的对称性,消除光子能带在晶体的布里渊区高对称点上的本征简并。(2)对于二维光子晶体的电磁波理论及周期介质中的Bloch波解做了详细的推导,给出了光子晶体中禁带存在的理论依据。同时以正方格子晶格的二维光子晶体为例,验证了电介质在空气圆孔中的排列存在E偏振和H偏振的光子带隙重叠区,称为绝对光子带隙。对于二维的光子晶体,两种本征偏振模式的光子能带结构可以独立地调节,以实现两者的光子带隙的最优重叠, 从而大大提高了二维光子晶体的完全带隙宽度。     

Bistability of an optical response of a photonic crystal with a dense resonant medium as a defect

Optical characteristics of a system consisting of a photonic crystal with a defect layer of a dense resonant medium described by the modified Bloch equation are considered. Transmission spectra are calculated and regions of existence of bistable optical response of the system are found. It is shown that the effect of internal reflection demonstrated by the dense resonant medium results in variation of reflection and transmission spectra of the photonic crystal and the loop width of the bistable response of the dense resonant medium is determined by the structure of the photonic crystal. Original Russian Text ? D.V. Novitsky, S.Yu. Mikhnevich, 2008, published in Optika i Spektroskopiya, 2008, Vol. 104, No. 6, pp. 987–991.     

半无限周期光子晶体全反射隧穿效应的共振机理

建立了一维半无限周期光子晶体的谐振腔模型.利用谐振腔的共振条件推导出全反射隧穿导带波长满足的解析公式,从理论上解释了一维半无限周期光子晶体的全反射隧穿效应产生的物理机理.利用波长的解析公式对全反射隧穿导带的波长随导带级数、腔光学厚度以及入射角的变化规律进行了研究,解释了一维半无限周期光子晶体的全反射隧穿效应的变化规律.将共振理论的结果与色散法的结果进行比较,其结果吻合.     

半无限周期光子晶体全反射隧穿效应的共振机理

建立了一维半无限周期光子晶体的谐振腔模型.利用谐振腔的共振条件推导出全反射隧穿导带波长满足的解析公式,从理论上解释了一维半无限周期光子晶体的全反射隧穿效应产生的物理机理.利用波长的解析公式对全反射隧穿导带的波长随导带级数、腔光学厚度以及入射角的变化规律进行了研究,解释了一维半无限周期光子晶体的全反射隧穿效应的变化规律.将共振理论的结果与色散法的结果进行比较,其结果吻合.     

New approaches for the fabrication of photonic structures of nonlinear optical materials

We revisited two different strategies to fabricate 1D photonic crystals of nonlinear optical dielectric materials based on ultrafast laser ablation of the surface of an RbTiOPO₄ crystal, and selective etching of ferroelectric domains of the surface of a periodically poled LiNbO₄ crystal. We evaluated their behaviour as Bragg diffraction gratings. We also presented the recent advances we developed in a new procedure of fabrication of 2D and 3D photonic crystals of KTiOPO₄ (KTP) grown on the surface of a KTP substrate by liquid phase epitaxial means within the pores of a silicon macroporous template. Optical, structural, morphological, and compositional characterization for the photonic crystals produced through this technique are presented.     

Channel drop filter using photonic crystal ring resonators for CWDM communication systems

In this paper, a new optical channel drop filter (CDF) using photonic crystal ring resonators (PCRRs) is presented. Using the two-dimensional (2D) finite-difference time-domain (FDTD) method in triangular lattice photonic crystal (PC) silicon rods, 100% forward dropping efficiency and a quality factor of more than 1000 can be achieved in third communication window while the resonant wavelength is 1550 nm. Through this novel (CDF), a multi-CDF operation with 100% drop efficiencies across all channels can be obtained. The proposed device could be used in future coarse wavelength division multiplexing (CWDM) communication systems.