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Author

Gianluca Ruffato

Other affiliations: AREA Science Park
Bio: Gianluca Ruffato is an academic researcher from University of Padua. The author has contributed to research in topics: Optical vortex & Plasmon. The author has an hindex of 18, co-authored 80 publications receiving 1077 citations. Previous affiliations of Gianluca Ruffato include AREA Science Park.


Papers
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Journal ArticleDOI
TL;DR: The high quality of the output beams confirms the applicability of these phase plates for the generation of high-order LG beams and compares with theoretical models and numerical simulations.
Abstract: Spiral phase plates for the generation of Laguerre-Gaussian (LG) beam with non-null radial index were designed and fabricated by electron beam lithography on polymethylmethacrylate over glass substrates. The optical response of these phase optical elements was theoretically considered and experimentally measured, and the purity of the experimental beams was investigated in terms of LG modes contributions. The far-field intensity pattern was compared with theoretical models and numerical simulations, whereas interferometric analyses confirmed the expected phase features of the generated beams. The high quality of the output beams confirms the applicability of these phase plates for the generation of high-order LG beams.

91 citations

Journal ArticleDOI
TL;DR: In this paper, a three-dimensional fabrication process by electron beam lithography was finely tuned in order to realize high-quality spiral phase plates (SPPs) for the generation of OAM-carrying optical beams.
Abstract: The discovery that light beams with a helical phase front carry orbital angular momentum (OAM) has enabled applications in many fields ranging from optical manipulation to quantum information processing and, recently, free-space information transfer and communications Here, a novel three-dimensional fabrication process by electron beam lithography was finely tuned in order to realize high-quality spiral phase plates (SPPs) for the generation of OAM-carrying optical beams Single- and multi-step SPPs have been realized for the generation of high-order Laguerre–Gaussian beams with different values of topological charge and radial index The optical response of these optical elements was experimentally investigated and compared with theoretical models

88 citations

Journal ArticleDOI
TL;DR: Due to its superior response, nanoporous gold patterns appear promising for the realization of compact plasmonic platforms for sensing purposes.
Abstract: The fabrication, characterization and functionalization of periodically patterned nanoporous gold layers is presented The material shows plasmonic properties in the near infrared range, with excitation and propagation of surface plasmon polaritons Functionalization shows a marked enhancement in the optical response in comparison with evaporated gold gratings, due to a great increase of the active surface Due to its superior response, nanoporous gold patterns appear promising for the realization of compact plasmonic platforms for sensing purposes

68 citations

Journal ArticleDOI
TL;DR: The design and fabrication of a compact diffractive optical element is presented for the sorting of beams carrying orbital angular momentum (OAM) of light, which paves the way for practical OAM multiplexing and demultiplexing devices for use in classical and quantum communication.
Abstract: The design and fabrication of a compact diffractive optical element is presented for the sorting of beams carrying orbital angular momentum (OAM) of light. The sorter combines a conformal mapping transformation with an optical fan-out, performing demultiplexing with unprecedented levels of miniaturization and OAM resolution. Moreover, an innovative configuration is proposed which simplifies alignment procedures and further improves the compactness of the optical device. Samples have been fabricated in the form of phase-only diffractive optics with high-resolution electron-beam lithography (EBL) over a glass substrate. A soft-lithography process has been optimized for fast and cheap replica production of the EBL masters. Optical tests with OAM beams confirm the designed performance, showing excellent efficiency and low cross-talk, with high fidelity even with multiplexed input beams. This work paves the way for practical OAM multiplexing and demultiplexing devices for use in classical and quantum communication.

68 citations

PatentDOI
TL;DR: In this article, a method and a system for the enhancement of the sensitivity in surface plasmon resonance (SPR) sensors based on metallic grating by exploiting the conical configuration is presented.
Abstract: A method and a system for the enhancement of the sensitivity in surface plasmon resonance (SPR) sensors based metallic grating by exploiting the conical configuration is presented. We consider the propagation of surface plasmon polaritons (SPPs) excited by light from the visible to infrared spectrum range, incident on a plasmonic grating at different directions by varying both the zenith and azimuthal angles. For specific azimuthal angles, SPPs propagate in the grating plane perpendicular to the incident light momentum. This is the condition that allows increasing the number of different excited SPPs modes largely. We exploit this effect to increase the sensor sensitivity with the change of refractive index of thin film on the plasmonic grating surface. Polarization effects also contribute to a further modes enhancement and increase the sensitivity. A scheme for a lab-on-chip implementation of a system that allows a parallel detection in microfluidic channels has been shown.

62 citations


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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: 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 …

33,785 citations

Journal ArticleDOI
TL;DR: The general overview of the field and the background for appropriate modelling of the physical phenomena are provided and the current state of the art and most recent applications of plasmon resonance in Au NPs are reported.
Abstract: 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.

1,205 citations

Journal ArticleDOI
TL;DR: This volume, more than most, explains the contributions of the laboratory to clinical medicine, and shedding light on fundamental metabolic sequences and biologic mechanisms.
Abstract: 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

1,117 citations

Journal ArticleDOI
TL;DR: The authors survey the steady refinement of techniques used to create optical vortices, and explore their applications, which include sophisticated optical computing processes, novel microscopy and imaging techniques, the creation of ‘optical tweezers’ to trap particles of matter, and optical machining using light to pattern structures on the nanoscale.
Abstract: 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.

1,016 citations

Journal ArticleDOI
TL;DR: An overview of the most significant aspects of surface-enhanced Raman scattering, and a representative selection of applications in the biomedical field, with direct and indirect protocols is provided.

474 citations