Electrically Driven Active Plasmonic Devices

The title of this book, Plasmonics: Principles and Applications, encompasses theory, technical issues, and practical applications which are of interest for diverse classes of the plasmonics. The book is a collection of the contemporary researches and developments in the area of plasmonics technology. It consists of 21 chapters that focus on interesting topics of modeling and computational methods, plasmonic structures for light transmission, focusing, and guiding, emerging concepts, and applications.

This book, edited by two of the most respected researchers in plasmonics, gives an overview of the current state in plasmonics and plasmonic-based metamaterials, with an emphasis on active functionalities and an eye to future developments. This book is multifunctional, useful for newcomers and scientists interested in applications of plasmonics and metamaterials as well as for established researchers in this multidisciplinary area.

A short introduction to the theory of surface plasmon polaritons (SPPs) is given. The application of the SPPs in on-chip signal processing is discussed. In particular, two concepts of plasmonic modulators are reported, wherein the SPPs are modulated by 40 Gbit/s electrical signals. Phase and Mach-Zehnder modulators employing the Pockels effect in electro-optic organic materials are discussed. A few micro-meter long SPP absorption modulator based on a thin layer of indium-tin-oxide is reported.

This thesis investigates the effect of the magnetic field on propagating surface plasmon polaritons (SPPs), or surface plasmons for short. Above all, it focuses on using the magnetic field as an external agent to modify the properties of the SPPs, and therefore achieving active devices. Surface plasmons are evanescent waves that arise at metal–dielectric interfaces. They can be strongly confined (beyond the light diffraction limit), and provide a strong enhancement of the electromagnetic field at the interface. These waves have led to the development of plasmonic circuitry, which is a key candidate as an alternative to electronic circuitry and traditional optical telecommunication devices, since it is faster than the former and less bulky than the latter. Adopting both a theoretical and an experimental point of view, the book analyzes the magnetic modulation in SPPs by means of an interferometer engraved in a multilayer combining Au and Co. In this interferometer, which acts like a modulator, the SPP magnetic modulation is studied in detail, as are the parameters that have a relevant impact on it, simple ways to enhance it, its spectral dependence, and the highly promising possibility of using this system for biosensing. The thesis ultimately arrives at the conclusion that this method can provide values of modulations similar to other active methods used in plasmonics.

The papers included in this issue of ECS Transactions were originally presented in the symposium ¿First International Symposium on Semiconductor and Plasmonics-Active Nanostructures for Photonic Devices and Systems¿, held during the 216th meeting of The Electrochemical Society, in Vienna, Austria from October 4 to 9, 2009.

Plasmonic nanoparticles (NPs) represent an outstanding class of nanomaterials that have the capability to localize light at the nanoscale by exploiting a phenomenon called localized plasmon resonance. The book is aimed at reviewing recent efforts devoted to utilize NPs in many research fields, such as photonics, optics, and plasmonics. In this fram

This book is a printed edition of the Special Issue "Liquid Crystals" that was published in Materials

Surface waves have drawn a significant attention and interest in the recent years in a broad range of commercial applications, while their commercial developments have been supported by fundamental and applied research studies. This book is a result of contributions of experts from international scientific community working in different aspects of surface waves and reports on the state-of-the-art research and development findings on this topic through original and innovative research studies. It contains up-to-date publications of leading experts, and the edition is intended to furnish valuable recent information to the professionals involved in surface wave analysis and applications. The text is addressed not only to researchers but also to professional engineers, students, and other experts in various disciplines, both academic and industrial, seeking to gain a better understanding of what has been done in the field recently and what kind of open problems are in this area.

The development of integrated electronic and photonic circuits has led to remarkable data processing and transport capabilities that permeate almost every facet of our daily lives. Scaling these devices to smaller and smaller dimensions has enabled faster, more power efficient and inexpensive components but has also brought about a myriad of new challenges. One very important challenge is the growing size mismatch between electronic and photonic components. To overcome this challenge, we will need to develop radically new device technologies that can facilitate information transport between nanoscale components at optical frequencies and form a bridge between the world of nano-electronic and micro-photonics. Plasmonics is an exciting new field of science and technology that aims to exploit the unique optical properties of metallic nanostructures to gain a new level of control over light-matter interactions. The use of nanometallic (plasmonic) structures may help bridge the size gap between the two technologies and enable an increased synergy between chip-scale electronics and photonics. In the first part of this dissertation we analyze the performance of a surface plasmon-polariton all-optical switch that combines the unique physical properties of small molecules and metallic (plasmonic) nanostructures. The switch consists of a pair of gratings defined on an aluminum film coated with a thin layer of photochromic (PC) molecules. The first grating couples a signal beam consisting of free space photons to SPPs that interact effectively with the PC molecules. These molecules can reversibly be switched between transparent and absorbing states using a free space optical pump. In the transparent (signal "on") state, the SPPs freely propagate through the molecular layer, and in the absorbing (signal "off") state, the SPPs are strongly attenuated. The second grating serves to decouple the SPPs back into a free space optical beam, enabling measurement of the modulated signal with a far-field detector. We confirm and quantify the switching behavior of the PC molecules by using a surface plasmon resonance spectroscopy. The quantitative experimental and theoretical analysis of the nonvolatile switching behavior guides the design of future nanoscale optically or electrically pumped optical switches. In the second part of the dissertation we provide a critical assessment of the opportunities for use of plasmonic nanostructures in thin film solar cell technology. Thin-film solar cells have attracted significant attention as they provide a viable pathway towards reduced materials and processing costs. Unfortunately, the materials quality and resulting energy conversion efficiencies of such cells is still limiting their rapid large-scale implementation. The low efficiencies are a direct result of the large mismatch between electronic and photonic length scales in these devices; the absorption depth of light in popular PV semiconductors tends to be longer than the electronic (minority carrier) diffusion length in deposited thin-film materials. As a result, charge extraction from optically thick cells is challenging due to carrier recombination in the bulk of the semiconductor. We discuss how light absorption could be improved in ultra-thin layers of active material making use of large scattering cross sections of plasmonic structures. We present a combined computational-experimental study aimed at optimizing plasmon-enhanced absorption using periodic and non-periodic metal nanostructure arrays.