Contents
List of contributors ix
1 Electromagnetic metamaterials and metasurfaces: historical
overview, characterization, and the effect of length scales 1
Christopher L. Holloway, Edward F. Kuester
1.1 Introduction 1
1.2 Electromagnetic behavior of ordinary materials 4
1.3 Metamaterials and periodic composites: length-scale effects 5
1.4 Metasurfaces 19
1.5 Isolated scatterers and one-dimensional array 29
1.6 Summary 29
References 30
2 Fundamentals of Mie scattering 39
Manuel Nieto-Vesperinas
2.1 Introduction 39
2.2 Uniform sphere: internal and scattered fields 39
2.3 Extinction and scattering of energy. Cross-sections 43
2.4 The scattering matrix 45
2.5 Scattering from a coated sphere 46
2.6 Optically active sphere 48
2.7 Scattering from an infinite circular cylinder 50
2.8 Mie resonances and natural modes 53
2.9 Small particles: dipolar approximation 56
2.10 Very small particles: the Rayleigh approximation 63
2.11 Effects due to interference between Mie resonances. Directional scattering 64
Acknowledgments 70
References 70
3 Control of scattering by isolated dielectric nanoantennas 73
Ramon Paniagua-Dominguez, Boris Luk’yanchuk, Arseniy I. Kuznetsov
3.1 Introduction 73
3.2 Resonant light scattering by single dielectric nanoparticles 74
3.3 Multipolar interference effects and directional scattering 79
3.4 Resonant scattering by dielectric nanoantennas 89
3.5 Conclusions and outlook 103
References 103
4 Controlling spontaneous emission with dielectric optical antennas 109
Nicolas Bonod
4.1 Introduction 109
4.2 Theory of spontaneous emission 109
4.3 Controlling the emission directivity 116
4.4 Fluorescence enhancement of electric and magnetic emitters 126
4.5 Conclusion and perspectives 135
Acknowledgments 136
References 136
5 Tailoring transmission and reflection with metasurfaces 145
Sergey Kruk, Yuri Kivshar
5.1 Introduction 145
5.2 Reflection 146
5.3 Transparency 149
5.4 Phase and polarization control 155
5.5 Absorption 157
5.6 Transmission and reflection at the oblique illumination 160
5.7 Transmission and reflection polarization phenomena 162
5.8 Fano resonances 166
5.9 Bound states in the continuum 167
References 171
6 Applications of wavefront control using nano-post based dielectric
metasurfaces 175
Andrei Faraon, Amir Arbabi, Seyedeh Mahsa Kamali, Ehsan Arbabi,
Arka Majumdar
6.1 Introduction 175
6.2 Capabilities for phase and polarization control enabled by dielectric
metasurfaces 175
6.3 Widefield imaging 178
6.4 Computational imaging 181
6.5 Focus scanning fluorescence imaging 182
6.6 Mechanically tunable devices 184
6.7 Devices based on simultaneous polarization and phase control 187
6.8 Devices exploiting spectral control 188
6.9 Conformal optics 190
6.10 Other applications 190
6.11 Outlook 191
References 191
7 Tunable metasurfaces and metadevices 195
Chengjun Zou, Isabelle Staude, Dragomir N. Neshev
7.1 Motivation and introduction 195
7.2 Mechanisms for tuning dielectric metasurfaces 196
7.3 Tunable functional metadevices 214
7.4 Outlook 217
References 217
8 Nonlinear and ultrafast effects 223
Maxim Shcherbakov, Sheng Liu, Igal Brener, Andrey Fedyanin
8.1 Introduction 223
8.2 Basics of nonlinear optics 224
8.3 Nonlinear optics in Mie-resonant nanostructures 225
8.4 Ultrafast phenomena in Mie-resonant nanostructures 237
8.5 Conclusions and outlook 241
References 242
9 Non-resonant dielectric metamaterials 249
Alexander Sprafke, Jörg Schilling
9.1 Definition of nonresonant spectral range 249
9.2 Theoretical description – homogenization and effective-medium
theories 250
9.3 Experimental observation – retrieval methods of effective
parameters 262
9.4 Spatial variation of effective dielectric constant – graded index
(GRIN) photonics 267
9.5 Disordered metamaterials 276
9.6 Conclusion 285
References 286
Index 289
Electromagnetic metamaterials and metasurfaces: historical overview, characterization, and the effect of length scales
Christopher L. Hollowaya, Edward F. Kuesterb aNational Institute of Standards and Technology, U.S. Department of Commerce, Boulder, CO, United States, bDepartment of Electrical, Computer, and Energy Engineering, University of Colorado at Boulder, Boulder, CO, United States
1.1 Introduction
The study of electromagnetic (EM) interactions with materials has a long and rich history dating back to Fresnel, Maxwell, Rayleigh, and many others [1–4]. Over these nearly 200 years, EM material development and applications have blossomed dramatically, culminating in the recent developments of metamaterials [5–16]. The prefix “meta” is a Greek preposition meaning (among other things) “beyond”. Metamaterials are novel, synthetic materials engineered to achieve unique properties not normally found in nature, i.e., materials beyond those occurring naturally. Metamaterials are often realized by arranging a set of small scatterers in a regular array throughout a region of space (Fig. 1.1), thus obtaining some desirable bulk behavior. Artificial dielectrics were early examples of these engineered materials. However, the term metamaterial is a newer designation that includes, but is not limited to, artificial dielectrics. Nor does the term metamaterial refer to classical periodic structures, such as what are now called photonic bandgap (PBG) structures or frequency-selective surfaces (FSSs). The term metamaterial refers to a material or structure with more exotic properties than artificial dielectrics, but which can still be described by bulk material parameters as natural materials can. One particular class of metamaterial that is being studied extensively consists of the so-called “double-negative” (DNG) materials [17–32] (also known as negative-index materials (NIM), backward-wave (BW) media, or left-handed materials (LHM)). Such materials have the property that their effective permittivity and effective permeability are simultaneously negative in a given frequency band. Another property not normally found in nature that can be achieved with metamaterials is that of near-zero refractive index. In this type of material, either the permittivity or permeability is designed to have its real part close to zero. Materials with unique properties such as these have a wide range of potential applications in electromagnetics at frequencies ranging from the low microwaves to optical, including shielding, lowreflection materials, novel substrates, antennas, electronic switches, devices, “perfect lenses,” resonators, and of course cloaking, to name only a few.
Initially, the pursuit of cloaking was the “Holy Grail” of these metamaterials and received much attention in the early years of metamaterial research. Cloaking (or the ability to “hide” an object) has appeared throughout the years in popular literature and, depending on your generation, examples include Tolkien’s ring, Romulan warships, and Harry Potter’s cloak. However, due to physical limitations (no broadband lossless metamaterials are available) cloaking materials have not come to practical fruition. So researchers have turned their attention to other exotic material properties. Properties that are of great interest for a wide range of applications include controllability (that is, a material whose properties can easily be changed over a wide range of frequencies), designs for a very narrow bandwidth, and engineering materials with tailored unnatural permittivities and permeabilities, e.g., materials with near-zero indices.
The concept of metamaterials has been extended to two-dimensional arrays (referred to as metasurfaces) [33,34]; see Figs. 1.1C and 1.2. These types of metastructures have an advantage over three-dimensional metamaterials because they take up less physical space and have the potential for lower losses. Metasurfaces have become a popular alternative to metamaterials. Applications of metasurfaces at frequencies from low microwave to optical have attracted great interest in recent years.
These applications in electromagnetics include controllable “smart” surfaces, miniaturized cavity resonators, novel waveguiding structures, angular-independent surfaces, absorbers, biomedical devices, terahertz switches, and fluid-tunable frequency-agile materials, to name only a few.