三维半导体GaAs量子阱微腔中的腔极化激元

半导体微腔中腔模和激子模耦合形成腔极化激元,三维微腔中由于横向限定腔模和激子模形成离散化的本征模式.本文计算了远离截止近似下,三维半导体微腔中空腔腔模的能量与微腔半径的关系;及腔模和激子模耦合后,三维半导体柱型微腔中具有相同角量子数和径向量子数的两个低阶腔模、重空穴激子模、轻空穴激子模耦合形成的腔极化激元能量随微腔半径变化的情况.结果表明随着微腔半径的减小腔模能量蓝移,腔模与相应的重空穴激子模、轻空穴激子模耦合形成的腔极化激元的三支随着微腔半径的减小存在明显的反交叉行为.随着微腔半径的变化,极化激元的三支所体现的模     

A compact leaky‐wave antenna using a planar spoof surface plasmon polariton structure

This article presents and validates a leaky‐wave antenna by using the spoof surface plasmon polariton (SSPP) technique. By properly designing the proposed SSPP unit, the SSPP wave can be switched between the confinement and radiation modes. A large radiation efficiency can be achieved by properly designing the modulation depth, which ensures that a compact SSPP leaky‐wave array can be realized by using a small number of SSPP radiation units. To verify the design, a prototype which consists of a SSPP feeding network and a 4 by 4 SSPP radiation units has been fabricated by using a low cost FR‐4 substrate. A good agreement between simulated and measured results has been obtained. The proposed array antenna shows the promising capability of the SSPP technique for leaky‐wave antenna applications.     

A tunable high-efficiency optical switch based on graphene coupled photonic crystals structure

A plasmonic device for high-efficiency optical switch is proposed based on graphene coupled photonic crystals structure. The finite-difference time-domain simulation results show that the transmission and reflection ratio can be controlled by tuning the parameters of the graphene strip, such as chemical potential or width. And the corresponding contrast ratio can be 25 and 26.8 for a single and double graphene strips coupled photonic crystals structure, respectively. The results in this paper will have potential application in nanosensors and integrated photonic circuits.     

Nanoimprint Lithography Facilitated Plasmonic-Photonic Coupling for Enhanced Photoconductivity and Photocatalysis

Imprint lithography has emerged as a reliable, reproducible, and rapid method for patterning colloidal nanostructures. As a promising alternative to top-down lithographic approaches, the fabrication of nanodevices has thus become effective and straightforward. In this study, a fusion of interference lithography (IL) and nanosphere imprint lithography on various target substrates ranging from carbon film on transmission electron microscope grid to inorganic and dopable polymer semiconductor is reported. 1D plasmonic photonic crystals are printed with 75% yield on the centimeter scale using colloidal ink and an IL-produced polydimethylsiloxane stamp. Atomically smooth facet, single-crystalline, and monodisperse colloidal building blocks of gold (Au) nanoparticles are used to print 1D plasmonic grating on top of a titanium dioxide (TiO₂) slab waveguide, producing waveguide-plasmon polariton modes with superior 10 nm spectral line-width. Plasmon-induced hot electrons are confirmed via two-terminal current measurements with increased photoresponsivity under guiding conditions. The fabricated hybrid structure with Au/TiO₂ heterojunction enhances photocatalytic processes like degradation of methyl orange (MO) dye molecules using the generated hot electrons. This simple colloidal printing technique demonstrated on silicon, glass, Au film, and naphthalenediimide polymer thus marks an important milestone for large-scale implementation in optoelectronic devices.     

Amplified spontaneous emission of surface plasmon polaritons with unusual angle-dependent response

Loss issues are fundamentally crucial for the application of surface plasmon polaritons (SPPs). In this study the amplified spontaneous emission (ASE) of SPPs in a typical Kretschmann configuration is observed and shows an unusually broadened angular response with increased pump intensity. Theoretical models are further developed to verify the results and understand the amplification of SPPs in Fourier space.     

Optical bistability of surface plasmon polaritons in nonlinear Kretschmann configuration

Optical bistability based on surface plasmon polaritons in the Kretschmann configuration involving a Kerr nonlinear medium is described by analytical solutions. The conditions of forming the optical bistability with different parameters are explored. The resonant angle of surface plasmon polaritons varying with the incident light intensity also generates the phenomenon of bistability. The system could form optical bistability with the special thickness of the metal film and incident angle. This kind of system has potential application in all-optical networks.     

Phase effects in guided mode resonances II: measuring the angular phase of a surface plasmon polariton

We show how the phase of a resonant interaction between a focused beam and a guided mode can be directly observed in a pupil imaging experiment, in which the irradiance leaving the pupil of a standard microscope is relayed to an image sensor through a combination Wollaston prism, calcite beam splitter and polarizer. We apply the method to the observation of a surface plasmon polariton resonance excited in a corrugated silver film fabricated using electron beam lithography. We discuss how this particular imaging configuration could be adapted for applications in plasmonic optical sensing.     

A dual-way directional surface-plasmon-polaritons launcher based on asymmetric slanted nanoslits

We theoretically design a device composed of two asymmetric slanted nanoslits to achieve the directionality of surface plasmon polaritons (SPPs). With proper inclination of the two slits, the desirable relative phase delay can be obtained. When the structure is illuminated by normal incident light, the SPPs can be controlled to deflect the specific direction due to light interference. The SPPs can be altered to the opposite direction when the illuminating light is changed inversely. We develop another way to tailor the relative phase delay by choosing the specific effective index for each slanted slit. In order to acquire higher directional excitation efficiency, our designs have been extended to periodic structures with the pairs of slanting slits. The finite element method is carried on to verify our designs. The simulations show that the best proportion of the SPP field intensity along two opposite directions reaches to around 30.     

Non-reciprocity and topology in optics: one-way road for light via surface magnon polariton

Abstract

We show how non-reciprocity and topology are used to construct an optical one-way waveguide in the Voigt geometry. First, we present a traditional approach of the one-way waveguide of light using surface polaritons under a static magnetic field. Second, we explain a recent discovery of a topological approach using photonic crystals with the magneto-optical coupling. Third, we present a combination of the two approaches, toward a broadband one-way waveguide in the microwave range.     

基于金属表面等离子体激元的光调制器研究

采用模式展开法研究了具有周期性空气孔亚波长阵列的“金属-介质-金属”结构对电磁波的透射特性。由于金属表面等离子体激元具有增强透射效应,使得该结构对电磁波有高通滤波的效果。当两层金属间介质的折射率发生变化时,该结构的透射谱中的峰值频率也随之移动。利用该特性,设计了光调制器结构,通过在该结构的上、下层金属加栽电压,即可改变中间层介质的折射率,从而对正入射的光波起到调制作用。研究表明,当介质折射率变化0．5％时,该调制器的调制深度达到88％。