Electronic circuits provide us with the ability to control the transport and storage of electrons. However, the performance of electronic circuits is now becoming rather limited when digital information needs to be sent from one point to another. Photonics offers an effective solution to this problem by implementing optical communication systems based on optical fibers and photonic circuits. Unfortunately, the micrometer-scale bulky components of photonics have limited the integration of these components into electronic chips, which are now measured in nanometers. Surface plasmon-based circuits, which merge electronics and photonics at the nanoscale, may offer a solution to this size-compatibility problem. Here we review the current status and future prospects of plasmonics in various applications including plasmonic chips, light generation, and nanolithography.

No abstract

We have experimentally observed the eigenmode splitting due to coupling of the evanescent defect modes in three-dimensional photonic crystals. The splitting was well explained with a theory based on the classical wave analog of the tight-binding ( TB) formalism in solid state physics. The experimental results were used to extract the TB parameters. A new type of waveguiding in a photonic crystal was demonstrated experimentally. A complete transmission was achieved throughout the entire waveguiding band. We have also obtained the dispersion relation for the waveguiding band of the coupled periodic defects from the transmission-phase measurements and from the TB calculations. PACS numbers: 42.70.Qs, 42.60.Da, 42.82.Et, 71.15.Fv The artificially created three-dimensional (3D) periodic structures inhibit the propagation of electromagnetic (EM) waves in a certain range of frequencies in all directions [1,2]. In analogy with electronic band gaps in semiconductors, these structures are called photonic band gap (PBG) materials or photonic crystals [3,4]. The initial interest in this area came from the proposal to use PBG crystals to control spontaneous emission in photonic devices [1]. However, the technological challenges restricted the experimental demonstrations and relevant applications of these crystals to millimeter wave and microwave frequencies [5][6][7]. Recently, Lin and Fleming reported a photonic crystal with a band gap at optical frequencies [8,9]. With this breakthrough, initially proposed applications like thresholdless semiconductor lasers [10] and single-mode light-emitting diodes [11,12] became feasible.By breaking the periodicity of the photonic crystal, it is possible to create highly localized defect modes within the photonic band gap, which are analogous to the localized impurity states in a semiconductor [13]. Photons hop from such a evanescent defect mode to the neighboring one due to overlapping of the tightly confined modes. This is exactly the classical wave analog of the tightbinding (TB) method in solid state physics [14,15]. The TB formulation has been proven to be very useful in studying electronic properties of solids [16,17]. Recently, the TB scheme was also successfully used for various photonic structures. Waveguiding along the impurity chains in photonic insulators [18], waveguiding through coupled resonators [19], and one-dimensional superstructure gratings [20] were theoretically investigated by using TB formalism. Lidorikis et al. tested the TB model by comparing the ab initio results of two-dimensional PBG structures with and without defects [21]. They obtained the TB parameters by an excellent fitting to ab initio results. Splitting of the coherent coupling of whispering gallery mode in quartz polystyrene spheres were reported and explained within the TB photon picture [22]. The optical modes in the micrometer-sized semiconductor coupled cavities were investigated by Bayer et al. [23].In this Letter, we investigated experimentally and theoretically the coupling between locali...

We demonstrate the use of surface Zeta potential measurements as a new tool to investigate the interactions of iron oxide nanoparticles and cowpea mosaic virus (CPMV) nanoparticles with human normal breast epithelial cells (MCF10A) and cancer breast epithelial cells (MCF7) respectively. A substantial understanding in the interaction of nanoparticles with normal and cancer cells in vitro will enable the capabilities of improving diagnostic and treatment methods in cancer research, such as imaging and targeted drug delivery. A theoretical Zeta potential model is first established to show the effects of binding process and internalization process during the nanoparticle uptake by cells and the possible trends of Zeta potential change is predicted for different cell endocytosis capacities. The corresponding changes of total surface charge of cells in the form of Zeta potential measurements were then reported after incubated respectively with iron oxide nanoparticles and CPMV nanoparticles. As observed, after MCF7 and MCF10A cells were incubated respectively with two types of nanoparticles, the significant differences in their surface charge change indicate the potential role of Zeta potential as a valuable biological signature in studying the cellular Biomed Microdevices

We propose a method to retrieve the effective constitutive parameters of a slab of bianisotropic metamaterial from reflection and transmission coefficients (or scattering parameters). In our retrieval method, only the scattering parameters in one propagation direction are used. Analytical inversion equations are derived in order to retrieve the effective parameters of the permittivity, permeability, and magnetoelectric coupling coefficient of the bianisotropic metamaterial. To demonstrate the validity of the method, we used it to retrieve the parameters of four different metamaterials, among which two were normal media without bianisotropy and the other two were bianisotropic media. In using our retrieval method, including bianisotropy, the intrinsic differences between a normal medium and a bianisotropic medium were illustrated clearly. Our simulation and retrieval results also corroborate the conclusions of the previously published literature.