نتایج جستجو برای: forbidden photonic band

تعداد نتایج: 163847  

Journal: :Physical review letters 2015
Sebabrata Mukherjee Alexander Spracklen Debaditya Choudhury Nathan Goldman Patrik Öhberg Erika Andersson Robert R Thomson

We demonstrate the first experimental realization of a dispersionless state, in a photonic Lieb lattice formed by an array of optical waveguides. This engineered lattice supports three energy bands, including a perfectly flat middle band with an infinite effective mass. We analyze, both experimentally and theoretically, the evolution of well-prepared flat-band states, and show their remarkable ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید بهشتی - دانشکده علوم 1388

چکیده ندارد.

Journal: :Optics express 2007
Alfonso R Alija Luis J Martínez Pablo A Postigo Jose Sánchez-Dehesa Matteo Galli Alberto Politi Maddalena Patrini Lucio C Andreani Christian Seassal Pierre Viktorovitch

A complete theoretical and experimental analysis of the photonic band structure for the Suzuki-phase lattice is presented. The band diagrams were calculated by two-dimensional plane wave expansion and three-dimensional guided-mode expansion methods. Angle resolved photoluminescence spectroscopy has been used to measure the emission of the photonic crystal structure realized in active InAsP/InP ...

2005
Zhongping Jian Jeremy Pearce Daniel M Mittleman

In this paper, we report our experimental study on two-dimensional photonic crystal slabs embedded inside parallel-plate metal waveguides, using terahertz time-domain spectroscopy. We observe that the temporal response of the photonic crystal slabs is significantly dispersed, indicative of strong dispersion near the edges of the photonic band gap. In the frequency domain, we observe several gap...

Journal: :Physical review letters 1996
Anderson Giapis

Absolute photonic band gaps in two-dimensional square and honeycomb lattices of circular crosssection rods can be increased by reducing the structure symmetry. The addition of a smaller diameter rod into the center of each lattice unit cell lifts band degeneracies to create significantly larger band gaps. Symmetry breaking is most effective at filling fractions near those which produce absolute...

Journal: :Physical review letters 2005
A Della Villa S Enoch G Tayeb V Pierro V Galdi F Capolino

This Letter presents a study of the local density of states (LDOS) in photonic quasicrystals. We show that the LDOS of a Penrose-type quasicrystal exhibits small additional band gaps. Among the band gaps, some exhibit a behavior similar to that typical of photonic crystals, while others do not. The development of certain band gaps requires large-size quasicrystals. It is explained by the long-r...

Recently, photonic crystals doped with liquid crystal (LC) material havegained much research interest. In this article new ternary one-dimensional photoniccrystal introduced and studied. The liquid crystal layer of 5CB and 5PCH is sandwichedby two dielectric layers. For the first time, we use four structures SiO2/UCF35/CaF2,SiO2/5CB/CaF2, NFK51/UCF35/NPSK53 and NFK51/5CB/NPSK53. The effect ofte...

2003
B. Cowan M. Javanmard R. Siemann

Photonic crystals have great potential for use as laserdriven accelerator structures. A photonic crystal is a dielectric structure arranged in a periodic geometry. Like a crystalline solid with its electronic band structure, the modes of a photonic crystal lie in a set of allowed photonic bands. Similarly, it is possible for a photonic crystal to exhibit one or more photonic band gaps, with fre...

Journal: :Optics express 2006
Satoru Shoji Remo Zaccaria Hong-Bo Sun Satoshi Kawata

We present laser interference patterning of three-dimensional photonic lattice structures with three-step three-beam irradiation. In contrast to one-step four-beam interference patterning, the proposed method makes it possible to continuously tune the lattice constant and the photonic band gap without distortion of the lattice shape. We analytically show that all fourteen Bravais lattices are p...

Journal: :Physical chemistry chemical physics : PCCP 2015
Robert Mitchell Rik Brydson Richard E Douthwaite

The propagation of light in photonic materials can be modified to increase the probability of photon absorption. Here we report the synthesis of composite materials comprising a photochemically inert photonic macroporous ZrO2 support decorated with photocatalytically active CdS nanoparticles. The relative energies of valence and conduction bands restrict photon absorption and catalysis to the C...

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