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1.
We analyze spatiotemporal light localization in truncated two-dimensional photonic lattices and demonstrate the existence of two-dimensional surface light bullets localized in the lattice corners or the edges. We study the families of the spatiotemporal surface solitons and their properties such as bistability and compare them with the modes located deep inside the photonic lattice. 相似文献
2.
We consider the transport of non-interacting electrons on two- and three-dimensional random Voronoi-Delaunay lattices. It was recently shown that these topologically disordered lattices feature strong disorder anticorrelations between the coordination numbers that qualitatively change the properties of continuous and first-order phase transitions. To determine whether or not these unusual features also influence Anderson localization, we study the electronic wave functions by multifractal analysis and finite-size scaling. We observe only localized states for all energies in the two-dimensional system. In three dimensions, we find two Anderson transitions between localized and extended states very close to the band edges. The critical exponent of the localization length is about 1.6. All these results agree with the usual orthogonal universality class. Additional generic energetic randomness introduced via random potentials does not lead to qualitative changes but allows us to obtain a phase diagram by varying the strength of these potentials. 相似文献
3.
X. Xu 《Applied physics. B, Lasers and optics》2007,86(3):467-471
The photon localization in disordered two-dimensional photonic crystal is studied theoretically. It is found that the mean
transmission coefficient in the photonic band decreases exponentially as the disorder degree increases, reflecting the occurrence
of Anderson localization. The strength of photon localization can be controlled by tuning the disorder degree in the photonic
crystal. We think the variation regular of the transmission coefficient in our disordered system is equivalent to that of
the scaling theory of localization.
PACS 42.70.Qs; 41.20.Jb; 42.25.Dd 相似文献
4.
Wang X Bezryadina A Chen Z Makris KG Christodoulides DN Stegeman GI 《Physical review letters》2007,98(12):123903
We report the first experimental observation of two-dimensional surface solitons at the boundaries (edges or corners) of a finite optically induced photonic lattice. Both in-phase and gap nonlinear surface self-trapped states were observed under single-site excitation conditions. Our experimental results are in good agreement with theoretical predictions. 相似文献
5.
We fabricate two-dimensional elliptic photonic lattices in iron-doped lithium niobate photorefractive crystal for the first time with optical induction method. The experimental setup of our method is very simple and flexible without complicated optical adjustment system. We analyze and verify the two-dimensional elliptic photonic lattices by plane wave guiding, far field diffraction pattern imaging, and Brillouin-zone spectroscopy. Induced elliptic photonic lattices can stably exist for a long time in the iron-doped lithium niobate crystal. The induced two-dimensional elliptic photonic lattices might offer an easy method to study generic band gap phenomena in anisotropic periodic structures. 相似文献
6.
We study the Anderson localization in two-dimensional lattices with long-range correlated hopping terms. The hopping energies along one lattice direction will be generated by a superposition of uncorrelated and long-range correlated contributions. Our numerical results strongly suggest the presence of a Kosterlitz-Thouless-like transition above a critical correlation degree. 相似文献
7.
S. Takeda S. Hamada R. Peretti P. Viktorovitch M. Obara 《Applied physics. B, Lasers and optics》2012,106(1):95-100
Transition process of optical modal properties induced by the introduction of randomness into random photonic crystals is
investigated by a computational method. We analyze an impulse response of two-dimensional triangular photonic crystals, in
which the positions of the air holes are slightly deviated to random directions. It is shown that the appropriate degree of
random departure from a perfect crystal state gives rise to multiple scattering of low group velocity band-edge modes and
supports their strong Anderson localization. The achieved confinement efficiency of light exceeds the one obtained in the
perfect photonic crystal state. 相似文献
8.
Stefano Longhi 《Annalen der Physik》2023,535(5):2200658
Anderson localization predicts that wave spreading in disordered lattices can come to a complete halt, providing a universal mechanism for dynamical localization. In the one-dimensional Hermitian Anderson model with uncorrelated diagonal disorder, there is a one-to-one correspondence between dynamical localization and spectral localization, that is, the exponential localization of all the Hamiltonian eigenfunctions. This correspondence can be broken when dealing with disordered dissipative lattices. When the system exchanges particles with the surrounding environment and random fluctuations of the dissipation are introduced, spectral localization is observed but without dynamical localization. Previous studies consider lattices with mixed conservative (Hamiltonian) and dissipative dynamics and are restricted to a semiclassical analysis. However, Anderson localization in purely dissipative lattices, displaying an entirely Lindbladian dynamics, remains largely unexplored. Here the purely-dissipative Anderson model in the framework of a Lindblad master equation is considered, and it is shown that, akin to the semiclassical models with conservative hopping and random dissipation, one observes dynamical delocalization in spite of strong spectral localization of the Liouvillian superoperator. This result is very distinct from delocalization observed in the Anderson model with dephasing, where dynamical delocalization arises from the delocalization of the stationary state of the Liouvillian. 相似文献
9.
基于Mie散射理论的光子晶体安德森定域化研究 总被引:1,自引:0,他引:1
基于Mie散射理论和低浓度近似,对磷化镓光子晶体的安德森定域化进行了理论计算,并分析了影响定域化参量的各种因素。结果表明,在浓度为10%,折射率比值大于3.8,无吸收状态下,中红外区出现了安德森定域化现象,并且随粒子半径的增大,定域化区向长波段移动,且基质折射率的增大使定域化现象减弱。研究结果为该类晶体的定域化现象提供了理论参考。 相似文献
10.
准周期晶格在冷原子领域被广泛研究,它使得人们可以在一维或者二维系统里研究扩展到安德森局域的转变. 2008年, Inguscio研究组在冷原子系统里制备了一维准周期晶格,并观测到了安德森局域化现象,这极大地推动了准周期系统的理论和实验研究.后来, Bloch研究组在制备的一维和二维准周期晶格中都观测到了多体局域的现象.最近,他们还在准周期晶格中成功观测到迁移率边以及存在迁移率边的系统的多体局域现象.这些冷原子实验推动了多体局域以及迁移率边等方向的研究.准周期晶格已经成为一个平台,它对很多物理现象的影响正在被广泛研究,并可以尝试在冷原子实验中观测到这种影响.本文结合作者的一些相关工作,对一维准周期晶格一些近期的研究进行了简要综述,介绍了一些相关的重要的冷原子实验,讨论了准周期晶格的一些重要性质,以及它对一些物理现象(比如拓扑态)的影响. 相似文献
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13.
We demonstrate both theoretically and experimentally that photonic lattices under self-defocusing nonlinearity support gap solitons in various shapes such as cross and H shapes. These solitons, with their intensity humps all in-phase, are stable against perturbations, thus they propagate robustly throughout the lattices. Based on this finding, we propose soliton-based text/image transmission through bulk photonic structures. 相似文献
14.
本文根据Mie散射理论和低浓度近似下,对在中红外区高折射率半导体材料AlP等做为散射体的类Opal光子晶体的安德森定域化进行了理论研究,发现在浓度为10%,折射率比值大于3.8,无吸收状态下,此类晶体将出现两个定域化区.同时为此类晶体的定域化研究提供了一个比较理想的处理方法. 相似文献
15.
L. Ge 《Annalen der Physik》2017,529(8)
Using one‐dimensional tight‐binding lattices and an analytical expression based on the Green's matrix, we show that anomalous minimum of the localization length near an isolated flat band, previously found for evanescent waves in a defect‐free photonic crystal waveguide, is a generic feature and exists in the Anderson regime as well, i.e., in the presence of disorder. Our finding reveals a scaling behavior of the localization length in terms of the disorder strength, as well as a summation rule of the inverse localization length in terms of the density of states in different bands. Most interestingly, the latter indicates the possibility of having two localization minima inside a band gap, if this band gap is formed by two flat bands such as in a double‐sided Lieb lattice. 相似文献
16.
D. Mihalache D. Mazilu F. Lederer 《The European physical journal. Special topics》2009,173(1):255-266
In the framework of the continuous-discrete cubic-quintic Ginzburg-Landau model, spatiotemporal dissipative solitons which
are highly confined inside two-dimensional photonic lattices are found numerically. The domains of existence in the relevant
parameter space, of in-phase (unstaggered) on-site (single-peaked), inter-site (double-peaked), and flat-top-like (four-peaked)
spatiotemporal dissipative solitons are determined. We show that the on-site solitons are stable in the whole domain of their
existence and we find the stability domains of both inter-site and flat-top-like solitons. We describe the complex instability-induced
scenarios of the dynamics of spatiotemporal discrete Ginzburg-Landau solitons in two-dimensional photonic lattices. 相似文献
17.
Rechtsman M Szameit A Dreisow F Heinrich M Keil R Nolte S Segev M 《Physical review letters》2011,106(19):193904
We study, experimentally and numerically, amorphous photonic lattices and the existence of band gaps therein. Our amorphous system comprises 2D waveguides distributed randomly according to a liquidlike model responsible for the absence of Bragg peaks, as opposed to ordered lattices with disorder which always exhibit Bragg peaks. In amorphous lattices the bands comprise localized states, but we find that defect states residing in the gap are more localized than the localization length of states within the band. Finally, we show how the concept of effective mass carries over to amorphous photonic lattices. 相似文献
18.
Huisman SR Nair RV Hartsuiker A Woldering LA Mosk AP Vos WL 《Physical review letters》2012,108(8):083901
We investigate the diffraction conditions and associated formation of stop gaps for waves in crystals with different Bravais lattices. We identify a prominent stop gap in high-symmetry directions that occurs at a frequency below the ubiquitous first-order Bragg condition. This sub-Bragg-diffraction condition is demonstrated by reflectance spectroscopy on two-dimensional photonic crystals with a centered rectangular lattice, revealing prominent diffraction peaks for both the sub-Bragg and first-order Bragg conditions. These results have implications for wave propagation in 2 of the 5 two-dimensional Bravais lattices and 7 out of 14 three-dimensional Bravais lattices, such as centered rectangular, triangular, hexagonal, and body-centered cubic. 相似文献
19.
根据Mie散射理论,在低浓度近似下,对中红外区由金属氧化物构成的反蛋白石光子晶体的禁带的存在区域,即光子定域化区进行了研究。发现在浓度为10%,此类晶体在中红外区将出现多个光子禁带区域,并且计算了影响定域化区域的各种因素。由此可知利用材料在剩余射线带内折射率小于1的特性,我们可以制备出中红外区和远红外区存在禁带的光子晶体。这一结果为反蛋白石晶体的研究提供了理论方法。 相似文献