Observation of total omnidirectional reflection from a one-dimensional dielectric lattice

We show that under certain conditions one-dimensional dielectric lattice possesses total omnidirectional reflection of incident light. The predictions are verified experimentally using Na3AlF6/ZnSe multilayer structure developed by means of standard optical technology. The structure was found to exhibit reflection coefficient more then 99% in the range of incident angles 0-86 (degree) at the wavelength of 632.8 nm for s-polarization. The results are believed to stimulate new experiments on photonic crystals and controlled spontaneous emission.Comment: 4 pages, 5 figures; submitted to Applied Physics

All-dielectric one-dimensional periodic structures for total omnidirectional reflection and partial spontaneous emission control

A remarkable property of one-dimensional all-dielectric periodic structures has recently been reported, namely a one-dimensional lattice can totally reflect electromagnetic wave of any polarization at all angles within a prescribed frequency region. Unlike their metallic counterpart, such all-dielectric omnidirectional mirrors are nearly free of loss at optical frequencies. Here we discuss the physics, design criteria and applications of the thin-film all-dielectric omnidirectional mirror. The experimental demonstration of the mirror is presented at optical frequencies.Comment: 6 pages, 9 figures; submitted to IEEE Journal of Lightwave Technolog

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We report on anisotropic light scattering in nanoporous anodic alumina. Light coming at various angles with respect to the pore axis was found to be scattered predominantly in the solid angle adjacent to the pore axis. Such scattering indicatrix we explain in the terms of redistributed local density of photon states in irregular nanostructured materials. In the case of porous alumina local density of photon states and light scattering probability are increased in the direction of the pore axis. We demonstrate by the example of PAA that nanostructured aperiodic materials can possess birefringent properties. We demonstrate and explain formation of the scattering rings by transmitted laser light in birefringent nanoporous anodic alumina.</p

Colloidal photoluminescent refractive index nanosensor using plasmonic effects

Fluorescence enhancement by metal nanostructures which is sensitive to refractive index n of an ambient medium is suggested as an operation principle of a novel refractive index sensor for liquids. Calculations are made for spherical and spheroidal Ag particles, and potential feasibility of sensitivity of the order of Δn=10-4 is demonstrated. Sensors of this type can be made fully colloidal with metal bodies deposited on a substrate or comprising a metal layer covering colloidal assembly of dielectric particles to serve as a test strip as well as placed on a fiber tip end to get local probing of refractive index in the tip-enhanced refractometry mode. Colloidal core-shell semiconductor nanocrystals may become the best candidates for this type of sensors whereas molecular probes may be affected by chemical properties of tested liquids

Colloidal Photoluminescent Refractive Index Nanosensor Using Plasmonic Effects

Fluorescence enhancement by metal nanostructures which is sensitive to refractive index n of an ambient medium is suggested as an operation principle of a novel refractive index sensor for liquids. Calculations are made for spherical and spheroidal Ag particles, and potential feasibility of sensitivity of the order of Δn=10-4 is demonstrated. Sensors of this type can be made fully colloidal with metal bodies deposited on a substrate or comprising a metal layer covering colloidal assembly of dielectric particles to serve as a test strip as well as placed on a fiber tip end to get local probing of refractive index in the tip-enhanced refractometry mode. Colloidal core-shell semiconductor nanocrystals may become the best candidates for this type of sensors whereas molecular probes may be affected by chemical properties of tested liquids

Anisotropic light scattering in nanoporous materials:A photon density of states effect

Similar to spontaneous emission of photons and inelastic (Raman) scattering, elastic (Rayleigh) scattering of light is controlled by spectral and spatial distribution of photon density of states, DOS (density of electromagnetic modes). However, to date Rayleigh scattering in nanoporous media has not become the subject of discussion in the context of photon DOS effects. In this paper, we consider light scattering in porous materials in the context of spectral, spatial, and angular redistribution of photon DOS in materials with pores whose size and spacing are of the order of light wavelength. The DOS effect results in predictable and controllable modification of scattering and can be purposefully used in certain light harvesting and illumination systems. A possible role of the effect in the cornea of eye is outlined for seeing at grazing incidence of light beams with respect to an eye pupil.</p

NATO Advanced Study Institute on Laser Control & Monitoring in New Materials, Biomedicine, Environment, Security & Defense

"Extreme Photonics & Applications" arises from the 2008 NATO Advanced Study Institute in Laser Control & Monitoring in New Materials, Biomedicine, Environment, Security and Defense. Leading experts in the manipulation of light offered by recent advances in laser physics and nanoscience were invited to give lectures in their fields of expertise and participate in discussions on current research, applications and new directions. The sum of their contributions to this book is a primer for the state of scientific knowledge and the issues within the subject of photonics taken to the extreme frontiers: molding light at the ultra-finest scales, which represents the beginning of the end to limitations in optical science for the benefit of 21st Century technological societies. Laser light is an exquisite tool for physical and chemical research. Physicists have recently developed pulsed lasers with such short durations that one laser shot takes the time of one molecular vibration or one electron rotation in an atom, which makes it possible to observe their internal electronic structure, thereby enabling the study of physical processes and new chemical reactions. In parallel, advances in micro- and nano-structured photonic materials allow the precise manipulation of light on its natural scale of a wavelength. Photonic crystals, plasmons and related metamaterials - composed of subwavelength nanostructures - permit the manipulation of their dispersive properties and have allowed the experimental confirmation of bizarre new effects such as slow light and negative refraction. These advances open a vista on a new era in which it is possible to build lasers and engineer materials to control and use photons as precisely as it is already possible to do with electrons. http://www.photonics.uottawa.ca/nato-asi-2008