Metals contain a sea of free electrons that are easily driven into collective oscillation by electromagnetic waves. As a result, small metal objects can serve as antennas that strongly scatter light. At the same time, extended metal surfaces have been shown to guide surface plasmons (photons bound to surface charge oscillations) that can confine light to deep sub-wavelength dimensions. Patterned metallic films can combine both the scattering and guiding properties of metals to capture and concentrate light from free space into a photodetector or to control the emission of light from emitting media. We first consider the wide range of functions that can be achieved in directing light emission with the help of smooth metallic films. We then describe how light interacts with patterned metallic films and present a detailed study of the effect of a single metallic groove on the scattering and surface plasmon guiding processes. This has lead to our discovery of new, exciting opportunities for dense optical functionality with non-periodically patterned metallic films. We show that a micronscale structure consisting of just two grooves in a metal film can lead to directional light coupling and wavelength splitting with a contrast ratio of 3:1. Our understanding is then generalized giving rise to a fast, simplified optimization of large non-periodic structures for a desired function. Lastly we consider the efficiency and bandwidth limits of coupling light through sub-wavelength slits for photodetection. We outline a path to efficient, spectrally selective detection which may find application in compact, polarization sensitive, multi-wavelength plasmonic detectors.

Metals contain a sea of free electrons that are easily driven into collective oscillation by electromagnetic waves. As a result, small metal objects can serve as antennas that strongly scatter light. At the same time, extended metal surfaces have been shown to guide surface plasmons (photons bound to surface charge oscillations) that can confine light to deep sub-wavelength dimensions. Patterned metallic films can combine both the scattering and guiding properties of metals to capture and concentrate light from free space into a photodetector or to control the emission of light from emitting media. We first consider the wide range of functions that can be achieved in directing light emission with the help of smooth metallic films. We then describe how light interacts with patterned metallic films and present a detailed study of the effect of a single metallic groove on the scattering and surface plasmon guiding processes. This has lead to our discovery of new, exciting opportunities for dense optical functionality with non-periodically patterned metallic films. We show that a micronscale structure consisting of just two grooves in a metal film can lead to directional light coupling and wavelength splitting with a contrast ratio of 3:1. Our understanding is then generalized giving rise to a fast, simplified optimization of large non-periodic structures for a desired function. Lastly we consider the efficiency and bandwidth limits of coupling light through sub-wavelength slits for photodetection. We outline a path to efficient, spectrally selective detection which may find application in compact, polarization sensitive, multi-wavelength plasmonic detectors.

Investigation of analysis methods of plasmonic crystals and metamaterials using traditional optical analysis, Planewave Expansion Method, and multiphysics software was conducted. 1D and 2D plasmonic crystals were studied and simulated for field enhancement. The sub-diffraction superlens and anisotropic lenses based on metamaterials were studied and an anisotropic lens was designed through computation. Comparison to existing work was made for evaluation of use in sub-diffraction limit nano-lithography. Investigation of manufacturing methods for thin-film-based plasmonic materials was carried-out. Ultra-flat metal methods involving template-stripping were used for superior surface performance key in plasmonic applications. Template-stripping through metal diffusion bonding and adhesive bonding were investigated, discussed, and employed with patterned ultra-flat metal films.

This book presents how metasurfaces are exploited to develop new low-cost single sensor based multispectral cameras. Multispectral cameras extend the concept of conventional colour cameras to capture images with multiple color bands and with narrow spectral passbands. Images from a multispectral camera can extract significant amount of additional information that the human eye or a normal camera fails to capture and thus have important applications in precision agriculture, forestry, medicine, object identifications, and classifications. Conventional multispectral cameras are made up of multiple image sensors each externally fitted with a narrow passband wavelength filters, optics and multiple electronics. The need for multiple sensors for each band results in a number of problems such as being bulky, power hungry and suffering from image co-registration problems which in turn limits their wide usage. The above problems can be eliminated if a multispectral camera is developed using one single image sensor.​

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.

This book presents the latest results of quantum properties of light in the nanostructured environment supporting surface plasmons, including waveguide quantum electrodynamics, quantum emitters, strong-coupling phenomena and lasing in plasmonic structures. Different approaches are described for controlling the emission and propagation of light with extreme light confinement and field enhancement provided by surface plasmons. Recent progress is reviewed in both experimental and theoretical investigations within quantum plasmonics, elucidating the fundamental physical phenomena involved and discussing the realization of quantum-controlled devices, including single-photon sources, transistors and ultra-compact circuitry at the nanoscale.