Preface

Plasmonics refers to the generation, detection, and manipulation of signals at optical frequencies along metal-dielectric interfaces at the nanometer scale. Similar to electronics and photonics, plasmonics follows the trend of miniaturizing optical devices, and its applications can be found in sensing, microscopy, optical communications, and bio-photonics. The era of plasmonics started in the 1950s with the discovery of surface plasmon polaritons (SPPs). Another milestone for plasmonic research was the development of surface-enhanced Raman scattering in the mid-1970s. However, it took several more decades for plasmonics to receive a new wave of attention. In particular, new manufacturing technologies in microelectronics have led to novel applications. SPPs are coherent electron oscillations traveling together with an electromagnetic wave along the interface between a dielectric material like silicon dioxide, glass or a polymer, and a metal like silver or gold. The SPP modes are strongly confined to their supporting interface, giving rise to strong light-matter interactions. In particular, the electron gas in the metal oscillates with the electromagnetic wave.

Plasmonics has attracted widespread attention in both science and industry, with the number of applications increasing rapidly. This book presents, in five chapters, a collection of recent advances in the broad field of plasmonics, including theory, simulation and fabrication aspects, along with emergent applications.

Lu He et al. provide a comprehensive analysis of the influence of geometry on plasmonic resonances in surface- and tip-enhanced Raman spectroscopy.

Kaweri Gambhir and Agnikumar G. Vedeshwar discuss the physical interactions of plasmons and their excitonic hybrids and describe their experimental realizations.

Ehab Awad investigates the design and optimization of a Bundt Optenna and demonstrates polarization insensitivity and ultra-broad bandwidth with a large fractional bandwidth within the near, short-wave, and mid-wave infrared bands.

Sanele Nyembe et al. discuss current challenges and developments of plasmonic nanostructures for molecular diagnostics and biosensors.

Hashem Rasha describes a plasmonic bowtie nano-antenna designed for biomedical applications.

We thank all the authors for their contributions. We also wish to express our thanks to the editorial staff of IntechOpen, particularly Ms. Karla Skuliber.

> **Patrick Steglich** Technische Hochschule Wildau, Wildau, Germany

Section 1

Fundamentals and

Optimization of Plasmonic

Nanostructures

**1**
