Ebrahim Forati
The density of Bloch electromagnetic states inside a one dimensional photonic crystal (1D PC) is formulated based on its dispersion relations. The formulation applied to any anisotropic medium with known dispersion relations and iso-frequency surfaces. Using a practical 1D PC parameters in the visible range, the density of Bloch states for different modes are calculated.
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Nonlinear Bloch modes in two-dimensional photonic lattices
利用相位印迹技术在正方形光子晶格中产生了不同类型的二维布洛赫波。通过分析与布里渊区高对称点相关的光束的线性衍射，我们探测了光子晶格中布洛赫模的局部色散，并通过观察非线性自作用效应区分了正常，异常和各向异性衍射的制度。
Surface Bloch waves mediated heat transfer between two photonic crystals
从理论上研究了热非平衡条件下两个相隔一定距离的光子晶体之间的非辐射换热。我们预测，由这些介质支持的表面布洛赫态耦合可以使热交换大于由光子晶体的基本组件制成的两个大质量均匀材料之间在相同的间距测量的热交换。这些结果可以在近场技术中找到广泛的应用。
Gyrotropic Bandgaps, Degeneracy Lifting and Selective Suppression of Bloch States in Photonic Systems
研究了双折射磁光子晶体在平面波导中非对称反向耦合时的简并破缺现象。基本的高阶本地正常模式耦合导致部分重叠的回旋带隙内的布里渊区和布洛赫模式传播的部分抑制。在带隙边缘的布洛赫模允许的偏振态中，发现了一个大的磁光主动重取向。
Bloch waves and non-propagating modes in photonic crystals
研究了电磁波在有限光子带隙结构中的传播。我们分析了导带和禁带的现象，我们表明，两个制度是要区分相对于界面附近的强场的存在。我们精确的域，有效介质理论是健全的。
We theoretically study light propagation in guided Bloch surface waves (BSWs) supported by photonic crystal ridges. We demonstrate that low propagation losses can be achieved just by a proper design of the multilayer to obtain photonic band gaps for both light polarizations. We present a design strategy based on a Fourier analysis that allows one to obtain intrinsic losses as low as 5 dB/km for a structure operating in the visible spectral range. These results clarify the limiting factors to light propagation in guided BSWs and represent a fundamental step towards the development of BSW-based …
Photonic Bloch oscillations and Zener tunneling in two-dimensional optical lattices
我们报告的第一个实验观察到的光子布洛赫振荡和齐纳隧道在二维周期性系统。我们研究了叠加在折射率斜坡上的正方形光子晶格中光束的传播，并证明了光从晶格带隙光谱的第一阶到高阶传输带的隧穿，与第一布里渊区内的光谱动力学和相应的初级光束的振荡相关。
Normal mode coupling and Bloch states in elliptically birefringent 1D photonic crystals
本文分析了椭圆双折射一维层状周期结构中频率与波矢色散的关系。研究发现，层与层之间存在的局域简正模偏振态变化会导致模式耦合，并影响系统的波矢色散和布洛赫态特性。
Extraction of optical Bloch modes in a photonic-crystal waveguide
我们在光子晶体波导上进行相敏近场扫描光学显微镜。观察到的复杂的场模式进行了分析，通过空间傅里叶变换，揭示了几个指导TE和TM的模式。使用Ha等人提出的重建算法（Opt. Lett. 34（2009）），我们将测量的二维场图案分解为传播布洛赫模式的叠加。这为研究近场测量中的特定模式开辟了新的可能性。我们应用该方法研究了类TE导模的横向行为，当接近带边时，该导模在周围的光子晶体中延伸得更深。
We propose a family of {\it local} $\cal{PT}$-symmetric photonic lattices with transverse index gradient $ω$, where the emergence of {\it stable} Bloch-Zener oscillations are controlled by the degree of non-Hermiticity $γ$ of the lattice. In the exact $\cal{PT}$-symmetric phase we identify a condition between $ω$ and $γ$ for which a wavepacket self -imaging together with a cascade of splittings and giant recombinations occurs at various propagation distances. The giant wavepacket recombination is further enhanced by introducing local impurities.
Photonic Bloch-dipole-Zener Oscillations in Binary Parabolic Optical Waveguide Arrays
本文研究了由两个渐逝耦合的异质光波导组成的二元抛物型光波导阵列（BPOWA）中光的传输和齐纳隧穿特性。由于布拉格反射，BPOWA获得了两个由在区边界处的minigap分开的minibands。在相图上，不同的参数会出现光振荡和齐纳隧穿的各种相干叠加。特别地，通过场演化分析，得到了布洛赫-齐纳振荡和一种不同类型的布洛赫-偶极子-齐纳振荡。这些结果在光分束和光波导器件中具有潜在的应用价值，并对光晶格中的相干现象有一定的解释作用。
Spatial distribution of the emission intensity in a photonic crystal: Self-interference of Bloch eigenwaves
对光子晶体中二能级原子（偶极）发射强度角分布的分析表明，在某些观测方向上，原子的发射率有增强的现象。这种增强是由于晶体的各向异性使许多具有不同波矢的布洛赫本征波在同一方向上聚束的结果。如果考虑发射强度的空间分布，则应考虑这些本征波的干涉。本文在经典宏观格林函数的渐近分析框架下，讨论了二能级原子的远场辐射模式。数值算例给出了一个二维正方形网格的聚合物中的空气孔。实验观察结果的相关性进行了讨论。
Floquet-Bloch lattices are systems in which wave packets are subjet to periodic modulations both in time and space, showing rich dynamics. While this type of lattices is difficult to implement in solid-state physics, optical systems have provided excellent platforms to probe their physics: among other effects, they have revealed genuine phenomena such as the anomalous Floquet topological insulator and the funnelling of light into localised interface modes. Despite the crucial importance of the band dispersion in the photon dynamics and the topological properties of the lattice, the direct expe…
Computation and visualization of photonic quasicrystal spectra via Blochs theorem
先前用于确定光子准晶体（PQC）光谱的方法依赖于使用大的超原胞来计算本征频率和/或局域态密度（LDOS）。在这篇文章中，我们提出了一种方法，通过这种方法，可以得到的能量谱和本征态的PQC通过求解麦克斯韦方程组在高维的任何PQC定义的标准切割和项目建设，适用于推广的布洛赫定理。此外，我们演示了如何可以计算能带结构的缺陷状态在高维超空间，没有额外的计算成本。作为一个概念的证明，这些一般的想法证明了一维准晶的简单情况下，这也可以通过简单的传输矩阵技术解决。
Single mode lasing and spectral narrowing in photonic crystal line-defect cavities via spatially selected Bloch modes
本文提出通过光学干涉空间泵浦特定布洛赫模式，实现光子晶体线缺陷腔激光器单模激射，边模抑制比超30dB，并改善线宽与噪声特性。
Soliton switching and Bloch-wave filtering in periodic photonic lattices
提出了一种基于周期光子结构中布洛赫波滤波的孤子开关新概念。以二元波导阵列为例，我们证明了属于不同光谱带隙的空间孤子可以选择性地从工程缺陷反射或透射通过工程缺陷，该工程缺陷充当布洛赫波的低通或高通滤波器。
A flexible Bloch mode method for computing complex band structures and impedances of two-dimensional photonic crystals
我们提出了一种灵活的方法，可以计算布洛赫模式，复杂的能带结构，和阻抗的二维光子晶体的散射数据产生的广泛可用的数值工具。该方法概括了以前的工作，依赖于专门的多极和有限元技术支撑的传递矩阵法。我们描述了模式提取的数值方法，并应用它计算了一个复杂的能带结构和设计了两个光子晶体减反射膜。我们这样做的频率，在其他方法失败，但仍然是重大的实际利益。
Light propagation in periodic environments is often associated with a number of interesting and potentially useful processes. If a crystalline optical potential is also linearly ramped, light can undergo periodic Bloch oscillations, a direct outcome of localized Wannier-Stark states and their equidistant eigenvalue spectrum. Even though these effects have been extensively explored in conservative settings, this is by no means the case in non-Hermitian photonic lattices encompassing both amplification and attenuation. Quite recently, Bloch oscillations have been predicted in parity-time-symmetr…
Phase transition to spatial Bloch-like oscillation in squeezed photonic lattices
我们提出了一个精确可解的波导晶格，其中包含非均匀耦合系数。这种结构为量子光学中的压缩数和压缩相干强度分布提供了一个经典的模拟，其中传输长度起着压缩振幅的作用。对于初始光束轮廓的任意分布，以封闭形式获得强度图案。我们还研究了通过在每个波导的传播常数（$ α$）上增加线性梯度来实现空间布洛赫振荡的相变。我们的分析结果表明，布洛赫振荡出现以上的传播常数的线性梯度（$ α> α_{c} $）的临界值。相变（在波导的传播特性中）是离散衍射和布拉格衍射之间竞争的结果。此外，光强度在临界点处沿着每个波导代数地衰减，而其在临界点（$ α< α_{c} $）以下指数地下降。
Photonic band structure and eigenmodes of magnetophotonic crystals
利用平面波展开法研究了二维和三维磁光子晶体的光子能带结构及其本征模的偏振特性。研究了磁化对光子能带结构和本征模的影响。研究了两种取向：面内磁化和垂直磁化。磁化引起的对称性破缺效应被证明是负责形成奇异的磁布洛赫模式，包括两个或更多的耦合对称和反对称布洛赫模式的相应的非磁性光子晶体。这些结果意味着非磁性光子晶体的非耦合态可以在磁性结构中被激发或耦合。我们发现磁布洛赫模的偏振态是非常复杂的。在垂直于平面磁化的特殊情况下，它们代表具有大纵向分量的面内椭圆（甚至圆）偏振波。
High-Q impurity photon states bounded by a photonic-band-pseudogap in an optically-thick photonic-crystal slab
我们表明，以二维光子晶体平板系统为例，即使在没有严格的光子带隙的情况下，也可以实现超过10 ^5的高品质因数（Q）。我们发现，平面内布洛赫模式的密度可以通过从有限尺寸的光子晶体边界，作为一个低Q谐振器创建额外的光子反馈控制。这种机制使显着减少之间的结合态和扩展布洛赫模式的耦合强度超过40倍。
Bloch-type photonic skyrmions in optical chiral multilayers
本研究通过量子自旋霍尔效应预测在手性材料中存在光子布洛赫型天空之王，拓展了光子天空之王的家族，并揭示了光子与磁性天空之王在手性特征上的相似性。
Tunable photonic Bloch oscillations in electrically modulated photonic crystals
从理论上研究了含非线性复合材料的一维光子晶体中光子布洛赫振荡的发生和可调谐性。由于复合材料的三阶非线性（克尔型非线性）增强，光子在倾斜的光子带内发生振荡，这是通过在这种光子晶体上施加沿垂直于层表面方向变化的梯度外泵浦电场实现的。PBO的可调谐性（包括幅度和周期）可以通过改变场梯度来容易地实现。通过适当的渐变泵浦AC或DC电场，太赫兹PBO可以出现并且覆盖电磁波谱中的太赫兹频带。
Versatile manipulation of nano- and microobjects underlies the optomechanics and a variety of its applications in biology, medicine, and lab-on-a-chip platforms. For flexible tailoring optical forces, as well as for extraordinary optomechanical effects, additional degrees of freedom should be introduced into the system. Here, we demonstrate that photonic crystals provide a flexible platform for nanoparticles optical manipulation due to both Bloch surface waves (BSWs) and the complex character of the reflection coefficient paving a way for complex optomechanical interactions control. We demonst…
Effective magnetic fields have enabled unprecedented manipulation of neutral particles including photons. In most studied cases, the effective gauge fields are defined through the phase of mode coupling between spatially discrete elements, such as optical resonators and waveguides in the case for photons. Here, in the paradigm of Bloch-wave modulated photonic crystals, we show creation of effective magnetic fields for photons in conventional dielectric continua for the first time, via Floquet band engineering. By controlling the phase and wavevector of Bloch waves, we demonstrated anomalous qu…
Based on a perturbative approach, we propose a simple and efficient method to engineer topological edge states in two dimensional magnetic photonic crystals. The topological edge states in the microstructures can be constructed and varied by altering the parameters of the microstructure according to the fieldenergy distributions of the Bloch states at the related Bloch wave vectors. The validity of the proposed method has been demonstrated by exact numerical calculations through three concrete examples. Our method makes the topological edge states 'designable'.
Fractional Bloch oscillations in photonic lattices
布洛赫振荡是量子粒子在周期势场中的振荡运动，是相干量子输运中最吸引人的效应之一。布洛赫振荡最初是在晶体中的电子的背景下研究的，它体现了物质的波动性质，并在各种不同的物理系统中发现。在这里，我们报告的分数布洛赫振荡的第一个实验观察，使用光子晶格作为一个模型系统的两粒子扩展玻色哈伯德哈密顿。在我们的光子模拟器中，在一维晶格上跳跃的两个相关粒子的动力学被映射到具有工程缺陷的二维晶格中的单个粒子的运动，并通过具有弯曲轴的方形波导晶格中的光传输来模仿。
Stopping and Time Reversal of Light in Dynamic Photonic Structures via Bloch Oscillations
理论分析表明，在不保持系统平移不变性的情况下，通过动态调谐谐振腔谐振，可以在耦合谐振腔光波导中实现光脉冲的存储和时间反转。该控制利用了光脉冲在折射率斜坡存在下的布洛赫振荡运动，因此它与Yanik和Fan在最近的工作中提出的绝热带压缩和反转机制相当不同[M.F. Yanik和S. Fan，Phys. Rev. Lett. 92，083901（2004）; Phys.Rev.Lett. 93，173903（2004）]。
Higher-order exceptional point and Landau-Zener Bloch oscillations in driven non-Hermitian photonic Lieb lattices
本文提出在具有复耦合的PT对称光子Lieb晶格中，通过折射率梯度调控实现三阶异常点，并揭示平带激发下Landau-Zener Bloch振荡的不对称能量跃迁、赝厄米传播及经过异常点时的二次发射现象。
Nearfield Vortex Dynamics of Supercell Bloch Modes
通过配对旋转三角结构，实现超细胞光子晶体中布洛赫模式的高Q因子转换，展示不同阶段的近场涡流分布和非线性特性，提升二次谐波产生效率。
We reveal a triangular-lattice planar photonic crystal supports Bloch modes with radially and azimuthally symmetric electric field distributions at the top band-edge of the first photonic band. Bifurcated from the corresponding Bloch modes, two cylindrical vector resonant modes are achieved by simply enlarging the central air-hole of the planar photonic crystal, which have high quality factors around 3,000 and small mode volume. The far-field radiations of the two resonant modes present high-quality cylindrical vector beam profiles. The resonant modes could be optimized by modifying the six ne…
Two-dimensional defect modes in optically induced photonic lattices
本文从理论上研究了二维光子晶格中局域缺陷和非局域缺陷引起的局域线性缺陷模。首先，当缺陷是局部的和弱的，从布洛赫带边缘分叉的缺陷模式的本征值解析推导。结果表明，在一个有吸引力（排斥）的缺陷，缺陷模式分叉出布洛赫带边缘正常（异常）的衍射系数。此外，缺陷模式的本征值和布洛赫带边缘之间的距离是指数小的函数的缺陷强度，这是非常不同的一维的情况下，这样的距离是平方小的缺陷强度。研究还发现，一些缺陷模分支不是从布洛赫带边缘分叉，而是从布洛赫带内的准边缘点分叉，这是非常不寻常的。其次，当缺陷是本地化的，但强，缺陷模式的数值确定。结果表明，排斥和吸引的缺陷可以支持各种类型的缺陷模式，如基本，偶极，四极和涡旋模式。这些模式存在于光子晶格的各种带隙中。随着缺陷强度的增加，当缺陷是排斥性的时，缺陷模式从较低的带隙移动到较高的带隙，但是当缺陷是吸引性的时，缺陷模式保持在每个带隙内，类似于一维的情况。当缺陷保持固定而施加的直流场（控制晶格势）增加时，观察到相同的现象。最后，如果缺陷是非本地化的（即，它持续在大的距离在晶格中），它表明，缺陷模式可以嵌入内部的连续谱，它们可以分叉出的边缘的连续谱代数，而不是指数。
Zener tunneling in two-dimensional photonic lattices
我们讨论了二维周期性光子结构中的带间光隧穿，这是最近在光诱导光子晶格实验中研究的结果[H。Trompeter等人，物理修订信函\textbf{96}，053903（2006）]。我们确定的齐纳隧道制度在交叉的两个布洛赫带，这发生在一个通用的情况下的布拉格反射时，布洛赫指数交叉的边缘的不可约布里渊区。类似地，当布洛赫指数通过布里渊区边缘上的高对称点时，高阶齐纳隧穿涉及四个布洛赫带。我们推导出简单的分析模型，描述隧道效应，并计算相应的隧穿概率。
Vectorial characterization of Bloch surface wave via one-dimensional photonic-atomic structure
本研究制备基于一维光子晶体的布洛赫波原子池，利用磁场调控BSW与热原子蒸气的耦合，通过类EIT特性变化重新定义倏逝波的法拉第、沃伊特几何并测量偏振电场分量比，为微型化原子研究提供新方向。
By applying a coupled-Bloch-mode approach, we have derived a simple expression for the transmission properties of photonic crystal (PhC) line-defect waveguides with a complex refractive index perturbation. We have provided physical insights on the coupling mechanism by analyzing the frequency dependence and relative strength of the coupling coefficients. We have shown the impact of the perturbation on the waveguide dispersion relation and how the gain-induced distributed feedback limits the maximum attainable slow-light enhancement of the gain itself. We have then applied our approach to analy…
We present an implementation of the Maxwell-Bloch (MB) formalism for the study of x-ray emission dynamics from periodic multilayer materials whether they are artificial or natural. The treatment is based on a direct Finite-Difference-Time-Domain (FDTD) solution of Maxwell equations combined with Bloch equations incorporating a random spontaneous emission noise. Besides periodicity of the material, the treatment distinguishes between two kinds of layers, those being active (or resonant) and those being off-resonance. The numerical model is applied to the problem of $Kα$ emission in multilayer m…
A hallmark of topological band theory in periodic media is that bulk properties are not affected by boundary conditions. Remarkably, in certain non-Hermitian lattices the bulk properties are largely affected by boundaries, leading to such major effects as the non-Hermitian skin effect and violation of the bulk-boundary correspondence. Here we unveil that non-unitary discrete-time quantum walks of photons in systems involving gain and loss show rather generally non-Bloch parity-time ($\mathcal{PT}$) symmetry breaking phase transitions, and suggest a bulk probing method to detect such boundary-d…
Absorbing boundary condition for Bloch-Floquet eigenmodes
提出了一种适用于光子晶体和超材料电磁频域模拟的吸收边界条件。该边界条件可以同时吸收周期晶体的多个布洛赫-弗洛奎本征模，包括传播模和消逝模。所讨论的光子晶体或超材料可以包括有损耗的、有源的、各向异性的甚至双各向异性的内含物。吸收边界条件依赖于Bloch-Floquet本征模的正交性条件，这里给出了一个广义的版本。我们测试了这种吸收边界条件的数值和目前的结果。
Mapping individual electromagnetic field components inside a photonic crystal
提出了一种绘制光子晶体内部绝对电磁场强度的方法。我们应用该方法来映射二维光子晶体平板在微波频率下的电场分量Ez。将平板放置在两个反射镜之间以选择布洛赫驻波，并在所得谐振器内扫描亚波长球形散射体。共振布洛赫频率根据散射体位置处的电场而偏移。为了映射电场分量Ez，我们测量板的反射和透射谱中的频移与散射体位置的关系。在没有任何可调参数的情况下，测量和计算之间存在非常好的一致性。
Quantum walks are processes that model dynamics in coherent systems. Their experimental implementations proved key to unveil novel phenomena in Floquet topological insulators. Here we realize a photonic quantum walk in the presence of a synthetic gauge field, which mimics the action of an electric field on a charged particle. By tuning the energy gaps between the two quasi-energy bands, we investigate intriguing system dynamics characterized by the interplay between Bloch oscillations and Landau-Zener transitions. When both gaps at quasi-energy values 0 and $π$ are vanishingly small, the Floqu…
The Lieb Lattice exhibits intriguing properties that are of general interest in both the fundamental physics and practical applications. Here, we investigate the topological Landau-Zener Bloch oscillation in a photonic Floquet Lieb lattice, where the dimerized helical waveguides is constructed to realize the synthetic spin-orbital interaction through the Floquet mechanism, rendering us to study the impacts of topological transition from trivial gaps to non-trivial ones. The compact localized states of flat bands supported by the local symmetry of Lieb lattice will be associated with other band…
The valleys of two-dimensional transition metal dichalcogenides (TMDCs) offer a new degree of freedom for information processing. To take advantage of this valley degree of freedom, on one hand, it is feasible to control valleys by utilizing different external stimuli like optical and electric fields. On the other hand, nanostructures are also used to separate the valleys by near field coupling. However, for both above methods, either required low-temperature environment or low degree of coherence properties limit their further applications. Here, we demonstrate all-dielectric photonic crystal…
Probing Long-Range Intensity Correlations inside Disordered Photonic Nanostructures
我们报告直接观察到的发展的长程空间强度相关性和增长的随机介质内的强度波动。我们制作了准二维无序光子晶体结构，并从第三个维度研究了光的输运。实验结果与理论计算结果吻合较好。我们能够通过简单地改变波导的几何形状来操纵无序波导内的长程强度相关性和强度波动。
Mapping the directional emission of quasi-two-dimensional photonic crystals of semiconductor nanowires using Fourier microscopy
控制纳米光子发射的色散和方向性是纳米光子学研究的主要目标之一。这种控制将允许开发高效的纳米源，即使是在单光子水平上。实现这一目标的方法之一是将发射耦合到周期性结构的布洛赫模式。在这里，我们提出了第一次测量的定向发射从纳米线光子晶体通过使用傅立叶显微镜。有了这项技术，我们有效地收集和解决纳米线的数值孔径内的显微镜物镜的定向发射。来自在每个纳米线中生长的异质结构的光发射由光子晶体的光子（布洛赫）模式控制。我们还证明，可以很容易地控制的方向性的发射渗透的光子晶体与高折射率的液体。这项工作为控制纳米线中的源的发射开辟了新的可能性。
We derive and validate a set of coupled Bloch wave equations for analyzing the reflection and transmission properties of active semiconductor photonic crystal waveguides. In such devices, slow-light propagation can be used to enhance the material gain per unit length, enabling, for example, the realization of short optical amplifiers compatible with photonic integration. The coupled wave analysis is compared to numerical approaches based on the Fourier modal method and a frequency domain finite element technique. The presence of material gain leads to the build-up of a backscattered field, whi…
In this article, we present a numerical study of the optical properties of a metal nanowire interacting with a localized cavity in a two dimensional photonic crystal. The nature of the modes, their wavelength and width are investigated as a function of the particle radius. It is shown in particular that a particle with diameter about the lattice constant presents very narrow resonances corresponding to hybrid photonic-plasmonic modes, where increased lifetime is attributed to the decrease of the radiative losses by interaction with the photonic crystal. These results open interesting applicati…
Band structure and Bloch states in birefringent 1D magnetophotonic crystals: An analytical approach
本文给出了椭圆双折射磁光子晶体的能带结构和布洛赫模的解析表达式。该模型结合了磁光薄膜器件中普遍存在的旋向性和线性双折射效应。得到了层状结构光子晶体中色散关系和布洛赫模的完整解析表达式，并分析了它们的性质。它表明，最近在文献中讨论的其他模型包含作为特殊的限制情况下，本文提出的配方。
Pulse trapping inside one-dimensional photonic crystal with relaxing cubic nonlinearity
本文从理论上研究了具有弛豫立方非线性的一维光子晶体中的脉冲俘获效应。我们分析了光局域化对脉冲强度的依赖关系，并解释了其物理机制与结构内部动态非线性腔的形成有关。我们搜索的参数（弛豫时间和脉冲持续时间）的最佳值的范围，并表明，脉冲捕获可以观察到只有正的非线性系数。我们认为这种效应对于实现光存储和光限幅是有用的。
We develop a semi-analytical model to describe bound states in the continuum (BICs) in photonic crystal slabs. We model leaky modes supported by photonic crystal slabs as a transverse Fabry-Perot resonance composed of a few propagative Bloch waves bouncing back and forth vertically inside the slab. This multimode Fabry-Perot model accurately predicts the existence of BICs and their positions in the parameter space. We show that, regardless of the slab thickness, BICs cannot exist below a cut-off frequency, which is related to the existence of the second-order Bloch wave in the photonic crystal…
Non-Bloch Theory for Spatiotemporal Photonic Crystals Assisted by Continuum Effective Medium
针对时空关联限制非布洛赫能带理论应用的问题，提出有效介质辅助的方法，建立了时空调制材料光子晶体的低频Floquet能带非布洛赫理论，并解析了其拓扑性质。
Periodically driven systems, characterised by their inherent non-equilibrium dynamics, are ubiquitously found in both classical and quantum regimes. In the field of photonics, these Floquet systems have begun to provide insight into how time periodicity can extend the concept of spatially periodic photonic crystals and metamaterials to the time domain. However, despite the necessity arising from the presence of non-reciprocal coupling between states in a photonic Floquet medium, a unified non-Hermitian band structure description remains elusive. Here, we experimentally reveal the unique Bloch-…
Different densities of electromagnetic states inside a one dimensional photonic crystal (1D PC) are studied. Hertz vector formalism is used to calculate Green tensor inside a layered structure, semi-analytically. Based on the obtained Green tensor, the local density of electromagnetic states (LDOS) and the density of states (DOS) inside a 1D PC are calculated and discussed. The Green tensor is also used to approximate the density of Bloch states inside the 1D PC and is compared with its exact calculation based on the 1D PC dispersion relations. Using a practical 1D PC parameters in the visible…
Bloch Siegert Physics in a Reconfigurable Photonic Binary Lattice
该研究通过可编程光子集成电路实现了二进制晶格中布洛赫-西格尔位移的实验验证，展示了强驱动量子光学现象和Floquet工程传输的可扩展测试平台。
Holographic polymer-dispersed liquid crystal Bragg grating integrated inside a solid core photonic crystal fiber
采用光致调制技术，将预聚物/液晶溶液注入到实芯光子晶体光纤（PCF）的中空通道中，利用可见光双光束全息术制作了聚合物/液晶基光纤布拉格光栅（PLC-FBG）。讨论了与光子带隙引导到渗透PCF中相关的制作过程和效果，以及PLC-FBG的表征。实验数据表明，PLC-FBG的液晶夹杂物导致高的热敏感性和弯曲敏感性。使用扫描电子显微镜检查PCF毛细管内的聚合物/液晶相分离的微观行为，同时进一步讨论。
Silicon is an excellent material for microelectronics and integrated photonics with untapped potential for mid-IR optics. Despite broad recognition of the importance of the third dimension, current lithography methods do not allow fabrication of photonic devices and functional microelements directly inside silicon chips. Even relatively simple curved geometries cannot be realized with techniques like reactive ion etching. Embedded optical elements, like in glass, electronic devices and better electronic-photonic integration are lacking. Here, we demonstrate laser-based fabrication of complex 3…
Determination of the Zak phase of one-dimensional photonic systems via far-field diffraction
本研究提出通过远场衍射光谱测定一维光子系统Zak相位的方法，推导了区中心与边界的衍射规律，经模拟与实验验证，并展示了拓扑保护界面态，为非厄米系统能带拓扑表征提供了简便途径。
Transversely Stable Soliton Trains in Photonic Lattices
本文报道了光学中横向稳定孤子串的存在。这些稳定的孤子串是在二维正方形光子晶格中发现的，当它们从第一布洛赫带内的鞍形衍射的X对称点分叉，并且它们的振幅超过一定的阈值时。我们还表明，孤子序列与低振幅或分叉的边缘的第一布洛赫带（伽玛和M点）仍然遭受横向不稳定性。这些结果在连续格点模型中得到，并进一步证实了离散模型。
Universal loss and gain characterization inside photonic integrated circuits
针对光子集成电路内部损耗与增益难以无损表征的问题，本文提出利用非线性光学器件作为光功率鉴别器的通用方法，实现组件级测量，精度优于0.1 dB，并验证于量子PIC。
Photonic crystals are periodic structures which prevent light propagation along one or more directions in certain frequency intervals. Their band spectrum is usually analyzed using Floquet-Bloch decomposition. This spectrum is located on the real axis, and it enters the complex plane when absorption and dispersion is considered in the dielectric permittivity of material constituents. Here, we review fundamental definition and properties of dispersion law and group velocity in photonic crystals and we illustrate them with numerical examples.
Dynamic Pattern of Finite-Pulsed Beams inside One-dimensional Photonic Band Gap Materials
从理论上研究了二维电磁脉冲通过一维光子晶体的动力学行为。采用坡印廷矢量上的时间期望积分作为到达时间[Phys. Rev. Lett. 84，2370，（2000）]，我们证明了电磁脉冲的超光速隧穿过程是净向前坡印廷矢量通过1DPC的传播，哈特曼效应是由于到达时间的饱和效应由于前向场和后向场的干扰效应，（从各层界面）发生在1DPC之前的区域和1DPC的前部。
Bloch-Zener oscillations (BZO), i.e. the interplay between Bloch oscillations and Zener tunneling in two-band lattices under an external dc force, are ubiquitous in different areas of wave physics, including photonics. While in Hermitian systems such oscillations are rather generally aperiodic and only accidentally periodic, in non-Hermitian (NH) lattices BZO can show a transition from aperiodic to periodic as a NH parameter in the system is varied. Remarkably, the phase transition can be either smooth or sharp, contrary to other types of NH phase transitions which are universally sharp. A dis…
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