There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

In the last two decades, plasmon resonance in gold nanoparticles (Au NPs) has been the subject of intense research efforts. Plasmon physics is intriguing and its precise modelling proved to be challenging. In fact, plasmons are highly responsive to a multitude of factors, either intrinsic to the Au NPs or from the environment, and recently the need emerged for the correction of standard electromagnetic approaches with quantum effects. Applications related to plasmon absorption and scattering in Au NPs are impressively numerous, ranging from sensing to photothermal effects to cell imaging. Also, plasmon-enhanced phenomena are highly interesting for multiple purposes, including, for instance, Raman spectroscopy of nearby analytes, catalysis, or sunlight energy conversion. In addition, plasmon excitation is involved in a series of advanced physical processes such as non-linear optics, optical trapping, magneto-plasmonics, and optical activity. Here, we provide the general overview of the field and the background for appropriate modelling of the physical phenomena. Then, we report on the current state of the art and most recent applications of plasmon resonance in Au NPs.

Surface plasmon resonance in gold nanoparticles: a review.

This book is one of our contemporary medical bibles. It needs no introduction; those who have frequent need of it know it very well, and those who use it less often seek it out on the library shelf when problems arise. The book is truly encyclopedic. Everything relevant discovered during the six-year intervals between publication finds its way into these pages. By today's standards, its 1,778 closely packed small-print pages are a bargain. The mutant gene is both hero and villain in this book. It is reponsible for the biochemical abnormality that results in disease, no matter how rare a given abnormality may be. By the same token, however, it is truly an experiment of nature, shedding light on fundamental metabolic sequences and biologic mechanisms. This volume, more than most, explains the contributions of the laboratory to clinical medicine. Each chapter seems to have been rewritten, so that the exciting

The Metabolic Basis Of Inherited Disease.

Thirty years ago, Coullet et al. proposed that a special optical field exists in laser cavities bearing some analogy with the superfluid vortex. Since then, optical vortices have been widely studied, inspired by the hydrodynamics sharing similar mathematics. Akin to a fluid vortex with a central flow singularity, an optical vortex beam has a phase singularity with a certain topological charge, giving rise to a hollow intensity distribution. Such a beam with helical phase fronts and orbital angular momentum reveals a subtle connection between macroscopic physical optics and microscopic quantum optics. These amazing properties provide a new understanding of a wide range of optical and physical phenomena, including twisting photons, spin-orbital interactions, Bose-Einstein condensates, etc., while the associated technologies for manipulating optical vortices have become increasingly tunable and flexible. Hitherto, owing to these salient properties and optical manipulation technologies, tunable vortex beams have engendered tremendous advanced applications such as optical tweezers, high-order quantum entanglement, and nonlinear optics. This article reviews the recent progress in tunable vortex technologies along with their advanced applications.

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Optical vortices 30 years on: OAM manipulation from topological charge to multiple singularities

A Review on Surface-Enhanced Raman Scattering.

In this work, we study how the Orbital Angular Momentum of a Plasmonic Vortex (an SPP carrying OAM) can be probed by the LSPR of nanoantennae conveniently integrated inside a Plasmonic Vortex Lens. We show that the turning “on” or “off” of the antennae acts as a fingerprint of the OAM of the PV and we discuss a particularly meaningful case. The integrated structure is fabricated and experimentally characterized in the near field. The results are in good agreement with the simulations and seem to prove the capability to transfer OAM properties control at the nanoscale.

Sub-wavelength confinement of the orbital angular momentum of light probed by plasmonic nanoantennae resonances

One of the most innovative ideas in recent electron optics is the so-called Orbital Angular Momentum (OAM) sorter [1][2]. This device is based on two confocal phase elements that strongly violate the cylindrical symmetry. In the stationary phase approximation, the first element produces a conformal mapping of the wavefunction between polar and Cartesian coordinates. The second element compensates for the transformation phase leaving only the input phase but remapped in the new coordinate system. Thanks to this behavior, the OAM sorter transforms an azimuthal phase gradient into a linear one, therefore being able to perform a map between angular momentum and linear momentum states and allowing for their efficient measurement.

/pdf/design-for-a-new-dipole-sorter-for-direct-and-dose-effective-2gnmzesnpn.pdf

Gianluca Ruffato

Papers

Sub-wavelength confinement of the orbital angular momentum of light probed by plasmonic nanoantennae resonances

Design for a New "Dipole-sorter" for Direct and Dose Effective Magnetic Dipole Measurement