In the last 30 days

• Open/close Surface plasmon–polariton length scales: a route to sub-wavelength optics

  William L Barnes 2006 J. Opt. A: Pure Appl. Opt. 8 S87 Tag this article

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  We look at four length scales associated with the surface plasmon–polariton (SPP) modes in the visible and near-infrared. We examine some of the consequences of these length scales for exploiting surface plasmon–polariton modes as a means to provide sub-wavelength optics. The four length scales discussed are the SPP wavelength, the SPP propagation distance, and the penetration depths of the field associated with the SPP into the dielectric and metal media that bound the interface that supports the SPP. Length scales spanning seven orders of magnitude, from nanometres to centimetres, are of relevance to SPPs. This paper concludes by identifying some of the challenges that lie ahead.

• Open/close Selective filling of photonic crystal fibres

  Kristian Nielsen et al 2005 J. Opt. A: Pure Appl. Opt. 7 L13 Tag this article

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  A model for calculating the time necessary for filling one or more specific holes in a photonic crystal fibre is made. This model is verified for water, and its enabling potential is illustrated by a polymer application. Selective filling of the core in an air-guide photonic crystal fibre is demonstrated for a polymer and for water. Launching light into such a hybrid-material core proves to be very easily done. Finally, a scheme for enabling access to the core alone, by use of a fusion splicer, is presented.

• Open/close Finite-element-based photoacoustic tomography in time domain

  Lei Yao and Huabei Jiang 2009 J. Opt. A: Pure Appl. Opt. 11 085301 Tag this article

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  We describe a finite element reconstruction algorithm for time-domain photoacoustic tomography. The algorithm is based on an iterative Newton method coupled with the time-domain Helmholtz-like photoacoustic wave equation subject to the first-order Bayliss–Turkel radiation boundary conditions. The algorithm is tested and evaluated using a series of simulated and tissue-like phantom data where objects are embedded in a circular background. The results show that quantitatively accurate photoacoustic images can be recovered using our time-domain reconstruction algorithm.

• Open/close Near-field photonics: surface plasmon polaritons and localized surface plasmons

  Anatoly V Zayats and Igor I Smolyaninov 2003 J. Opt. A: Pure Appl. Opt. 5 S16 Tag this article

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  Surface plasmon polaritons and localized surface plasmons are discussed in the context of photonic applications. Near-field imaging of scattering, reflection, interference and localization of surface polaritons is reviewed, and approaches for the implementation of elements of surface polariton optics are presented. Surface plasmon polaritonic crystals and their role in the determination of optical properties of periodically nanostructured metal films are described. Non-linear effects related to surface polaritons and localized surface plasmons allowing control of optical properties of nanostructured metal films with light are discussed. Surface plasmon optics opens up numerous possibilities for application of these intrinsically two-dimensional excitations in passive and active devices of all-optical integrated circuits.

• Open/close The role of localized surface plasmon modes in the enhanced transmission of periodic subwavelength apertures

  A Degiron and T W Ebbesen 2005 J. Opt. A: Pure Appl. Opt. 7 S90 Tag this article

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  After reviewing the present understanding of the transmission properties of single apertures and the enhanced transmission through hole arrays, experimental results are presented which show how localized surface plasmon (LSP) modes of individual apertures contribute to the transmission peaks associated with the periodic arrays. In particular, it is shown that the surface plasmon polaritons (SPPs) of the periodic structure dominate the spectral signature of the arrays. The results also indicate that the LSP of each hole can interact and that this can be controlled by appropriate arrangement of the apertures in the array.

• Open/close Plasmonic and metamaterial cloaking: physical mechanisms and potentials

  Andrea Alù and Nader Engheta 2008 J. Opt. A: Pure Appl. Opt. 10 093002 Tag this article

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  Artificial materials, metamaterials and plasmonic media have recently received tremendous attention from the scientific communities, media and the general public, following novel ideas and suggestions for their potential use in a variety of applications such as cloaking. Here we briefly review and highlight some of the available solutions for invisibility and cloaking that employ metamaterials and plasmonic materials at various frequencies. We briefly overview some of the different cloaking mechanisms recently proposed in the literature, such as plasmonic cloaking based on scattering cancelation, coordinate-transformation cloaking and anomalous localized resonances for cloaking, in particular providing some details for scattering-cancelation-based plasmonic cloaking. We mention the main analogies and differences among these various approaches and we discuss some possible ideas for realizations and applications of these results, with particular attention to the physical phenomena involved.

• Open/close Chiral metamaterials: simulations and experiments

  Bingnan Wang et al 2009 J. Opt. A: Pure Appl. Opt. 11 114003 Tag this article

  Article References Full text PDF (1.72 MB)

  Electromagnetic metamaterials are composed of periodically arranged artificial structures. They show peculiar properties, such as negative refraction and super-lensing, which are not seen in natural materials. The conventional metamaterials require both negative and negative μ to achieve negative refraction. Chiral metamaterial is a new class of metamaterials offering a simpler route to negative refraction. In this paper, we briefly review the history of metamaterials and the developments on chiral metamaterials. We study the wave propagation properties in chiral metamaterials and show that negative refraction can be realized in chiral metamaterials with a strong chirality, with neither nor μ negative required. We have developed a retrieval procedure, adopting a uniaxial bi-isotropic model to calculate the effective parameters such as n _± , κ, and μ of the chiral metamaterials. Our work on the design, numerical calculations and experimental measurements of chiral metamaterials is introduced. Strong chiral behaviors such as optical activity and circular dichroism are observed and negative refraction is obtained for circularly polarized waves in these chiral metamaterials. We show that 3D isotropic chiral metamaterials can eventually be realized.

• Open/close Surfaces with holes in them: new plasmonic metamaterials

  F J Garcia-Vidal et al 2005 J. Opt. A: Pure Appl. Opt. 7 S97 Tag this article

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  In this paper we explore the existence of surface electromagnetic modes in corrugated surfaces of perfect conductors. We analyse two cases: one-dimensional arrays of grooves and two-dimensional arrays of holes. In both cases we find that these structures support surface bound states and that the dispersions of these modes have strong similarities with the dispersion of the surface plasmon polariton bands of real metals. Importantly, the dispersion relation of these surface states is mainly dictated by the geometry of the grooves or holes and these results open the possibility of tailoring the properties of these modes by just tuning the geometrical parameters of the surface.

• Open/close Raman spectra of polymethyl methacrylate optical fibres excited by a 532 nm diode pumped solid state laser

  K J Thomas et al 2008 J. Opt. A: Pure Appl. Opt. 10 055303 Tag this article

  Article References Full text PDF (201 KB)

  Polymethyl methacrylate (PMMA) optical fibres are fabricated by a preform drawing process. The Raman spectra of PMMA fibres are recorded using a diode pumped solid state laser emitting at 532 nm and a CCD-spectrograph in the 400–3800 cm ⁻¹ range. The variation of the Raman intensity with the length of the optical fibre is studied. Investigations are carried out on the variation of FWHM of the Raman peak at 2957 cm ⁻¹ with the length of the optical fibre and pump power. The differential scattering cross section and gain coefficient of the Raman peak at 2957 cm ⁻¹ in PMMA are calculated in relation to that of toluene.

• Open/close Micromachining of photonic devices by femtosecond laser pulses

  G Della Valle et al 2009 J. Opt. A: Pure Appl. Opt. 11 013001 Tag this article

  Article References Full text PDF (2.87 MB)

  In this paper we review the micromachining of photonic devices in several materials by means of ultrashort laser pulses. The physical mechanisms underlying the refractive index modification and the different laser systems used to induce such modification are discussed. A thorough review of the photonic devices demonstrated with the femtosecond laser microfabrication technique is presented. In particular, this paper is focused on photonic devices based on optical waveguides. The devices are organized into two categories: passive and active devices. In the former category power splitters, directional couplers, interferometers and Bragg gratings are reviewed, while in the latter amplifiers and lasers are discussed. Finally, conclusions and future perspectives of femtosecond laser micromachining in photonics are provided.