Optical Antennas

Cover......Page 1
Title......Page 5
Copyright......Page 6
Dedication......Page 7
Contents......Page 9
Preface......Page 17
Contributors......Page 20
Notation......Page 24
Part I FUNDAMENTALS......Page 27
1.1 The near-field......Page 29
1.2 Energies and photons......Page 30
1.4 Scanning near-field optical microscopy......Page 31
1.5 Problems of near-field optical microscopy......Page 33
1.7 Optical antennas......Page 34
1.8 Conclusions and outlook......Page 36
2.1 Introduction......Page 37
2.2 Nanoantennas and optical nanocircuits......Page 38
2.2.1 Optical nanocircuit theory......Page 39
2.2.2 Nanoantennas as optical lumped elements......Page 40
2.2.3 Other quantities of interest for optical antenna operation......Page 43
2.3.1 Loading, impedance matching and optical wireless links......Page 44
2.3.2 Optimizing bandwidth and sensitivity with nanoloads......Page 47
2.3.3 Optical nonlinearities as variable nanoloads......Page 50
Acknowledgments......Page 51
3.1 Introduction......Page 52
3.2.1 Definition......Page 53
3.2.2 A vacuum......Page 54
3.2.3 A microcavity......Page 56
3.2.4 A dipolar nanoantenna......Page 57
3.2.5 Comparison of a microcavity and a nanoantenna......Page 58
3.2.6 Ohmic and radiative losses......Page 59
3.3.1 A two-level system......Page 60
3.3.2 Impedance and multiple scattering......Page 62
General case: equivalent circuit and eigenfrequencies......Page 63
Weak coupling regime......Page 64
Strong coupling regime......Page 65
3.4.2 Conjugate impedance matching condition......Page 67
3.4.3 Maximum absorption by a metallic nanoparticle......Page 68
3.4.4 Fluorescence enhancement by metallic nanoparticles......Page 69
3.5 Conclusions......Page 71
4.1 Introduction......Page 72
4.2.1 Configuration......Page 76
4.2.2 Theory......Page 77
4.2.3 Coated-nanoparticle materials and gain models......Page 78
4.3 Results and discussion......Page 79
4.3.2 Near-field results......Page 80
4.3.3 Influence of the dipole location......Page 82
4.3.4 Additional effects – transparency......Page 84
4.3.5 Additional coated-nanoparticle cases......Page 85
4.4.1 Nanoparticle model......Page 86
4.4.2 Results and discussion......Page 87
4.5 Conclusions......Page 89
5.1.1 Field enhancement......Page 90
5.1.2 Spectral response......Page 91
5.1.3 Shape......Page 93
Aspect ratio......Page 95
Sharpness......Page 97
Coupling......Page 98
5.2 Surface-enhanced Raman scattering......Page 99
5.3 Surface-enhanced infrared absorption......Page 101
5.4 Metal-enhanced fluorescence......Page 102
5.5 Quantum effects in nanoantennas......Page 105
6.1.1 Optical antennas......Page 107
Definition......Page 108
Optical antennas as cavities......Page 109
Excitation, emission and dissipation rates......Page 110
6.1.3 Resonant coupling of antenna and emitter......Page 113
6.2.2 The monopole antenna case......Page 115
Localization: role of the antenna excitation field......Page 116
Enhancement: role of the antenna resonance......Page 118
The monopole antenna case......Page 119
The dipole antenna case......Page 121
The dipole antenna case......Page 122
The Yagi–Uda antenna case......Page 123
6.4 Conclusions and outlook......Page 125
Quantum optics......Page 126
Classical optics......Page 127
Near-field microscopy......Page 128
7.2 Microcavities......Page 129
7.3 Antennas......Page 130
7.3.1 Small antennas......Page 131
7.4.1 Planar antennas......Page 133
7.4.2 Microcavities......Page 134
7.4.3 Plasmonic nanoantennas......Page 135
7.4.4 Metallo-dielectric hybrid antennas......Page 137
7.5.2 Plasmonic nanoantennas......Page 139
7.5.3 Planar antennas......Page 140
7.6 Antennas immersed in vacuum fluctuations: Casimir and van der Waals interactions......Page 142
7.7 Scanning near-field optical microscopy......Page 144
7.8 Outlook......Page 146
Acknowledgments......Page 147
8.1 Introduction......Page 148
8.2.1 Origin of optical nonlinearities in nanoantennas......Page 149
8.2.2 Nonlinear susceptibilities of optical materials......Page 152
8.3.1 Nanoscale and macroscale nonlinear phenomena......Page 153
8.3.3 Nonlinear polarization in nanoparticles......Page 154
8.4 Nonlinearities in coupled antennas and arrays......Page 155
8.4.1 Enhancement of metal nonlinearities......Page 156
8.4.2 Enhancement of nonlinearities in surrounding media......Page 157
8.4.3 TPL nonlinear microscopy of coupled particles......Page 158
8.5 Conclusions and outlook......Page 159
9.1 Introduction......Page 161
9.2 Local-field control principles......Page 164
9.2.1 Fundamental quantities......Page 165
9.2.2 Spectral enhancement......Page 166
9.2.3 Local polarization-mode interference......Page 168
9.2.4 Local pulse compression......Page 169
9.2.5 Optimal control......Page 170
9.2.6 Analytic optimal control rules......Page 172
9.2.7 Time reversal......Page 174
9.2.8 Spatially shaped excitation fields......Page 175
9.3.1 Spatial excitation control......Page 176
9.3.2 Spatiotemporal excitation control......Page 178
9.3.3 Propagation control......Page 179
9.4.1 Space–time-resolved spectroscopy......Page 180
9.4.3 Unconventional excitations......Page 181
9.5 Conclusions and outlook......Page 182
Part II MODELING, DESIGN AND CHARACTERIZATION......Page 183
10.1 Introduction......Page 185
10.2 The numerical solution of Maxwell equations......Page 186
10.2.1 Finite-difference time-domain method......Page 187
10.2.2 Finite-differences method......Page 188
10.2.3 Finite-elements method......Page 189
10.2.4 Volume integral-equation method......Page 191
10.2.5 Boundary-element method......Page 192
10.3 Validity checks......Page 194
10.4 Modeling realistic optical antennas......Page 195
10.5 Tuning the antenna properties......Page 197
Acknowledgments......Page 200
11.1 Introduction......Page 201
11.2 Quantum effects on the near-field......Page 203
11.3 Plasmon–exciton hybridization......Page 207
11.4 Near-field effects on spectroscopy......Page 213
11.4.1 Surface-enhanced Raman scattering......Page 214
11.4.2 Surface-enhanced fluorescence......Page 217
11.5 Near-field effects on molecular photochemistry......Page 218
11.5.2 Photochemical enhancement mechanism......Page 219
11.6 Conclusions and outlook......Page 222
12.1 Introduction......Page 223
12.2 Theoretical background......Page 225
12.3.1 Sphere dimers......Page 229
12.3.2 Nano-rods......Page 233
12.3.3 Cylinders......Page 235
12.4 Enhancement and localization versus distance in particle dimers......Page 237
12.5 Conclusions......Page 239
13.1 Introduction......Page 241
13.2 Fabrication of single-crystalline antennas......Page 242
13.2.1 Role of the dielectric function......Page 243
13.2.2 Effects of geometry and multicrystallinity......Page 245
13.2.3 Fabrication issues......Page 246
13.2.4 Single-crystalline nanostructures......Page 247
13.3.1 Far-field scattering......Page 249
13.3.2 Determining the near-field intensity enhancement......Page 250
13.3.3 Emission directivity and coupling to quantum emitters......Page 256
13.4 Conclusions and outlook......Page 258
14.1 Introduction......Page 260
14.2.1 Instrumental setup......Page 262
14.2.2 The photoemission process......Page 264
14.3.1 Local near-field mapping......Page 266
14.3.3 Observing and controlling the near-field distribution......Page 270
14.3.4 Nonlinearities on structured surfaces......Page 273
14.4 Time-resolved two-photon photoemission......Page 274
14.4.1 Phase-averaged time-resolved PEEM......Page 276
14.4.2 Phase-resolved PEEM......Page 278
14.5.2 Magneto-plasmonics......Page 279
14.6 Conclusions and outlook......Page 280
Acknowledgments......Page 281
15.1 Introduction......Page 282
15.2.1 The array factor......Page 283
15.2.2 Two-dimensional planar arrays and phased arrays......Page 285
15.2.3 Directionality enhancement......Page 286
15.3.1 Effective antenna length......Page 287
15.4 The optical Yagi–Uda antenna – linear array of plasmonic dipoles......Page 288
15.4.2 Design of receiving optical Yagi–Uda antennas......Page 290
15.4.3 Characterization of receiving optical Yagi–Uda antenna......Page 291
15.5.1 Characterization of planar optical antenna arrays......Page 294
15.5.2 Fabricating three-dimensional nanoantennas......Page 296
15.5.3 Optical properties......Page 297
15.5.4 Experimental characterization......Page 298
15.6 Applications of optical antenna arrays......Page 300
15.6.1 Phased arrays for optical wavelengths......Page 301
15.6.2 Optical antenna links......Page 302
16.1 Introduction......Page 303
16.2 Conventional methods to create nanoantennas......Page 305
16.3 Soft nanolithography......Page 306
16.3.3 Nanopatterned template......Page 307
16.3.4 Optical antenna arrays......Page 308
16.4 Strongly coupled nanoparticle arrays......Page 309
16.5 Metal–insulator–metal nanocavity arrays......Page 311
16.6 Three-dimensional bowtie antenna arrays......Page 315
16.7 Conclusions and outlook......Page 319
17.1 Introduction......Page 320
17.2 Self-assembled magnetic clusters......Page 321
17.3 Plasmonic Fano-like resonances......Page 329
17.4 DNA cluster assembly......Page 337
17.5 Conclusions and outlook......Page 342
Acknowledgments......Page 343
Part III APPLICATIONS......Page 345
18.1 Introduction......Page 347
18.2 Coupling plasmonic antennas to semiconductors......Page 348
18.3 Plasmonic antennas for information technology and energy harvesting......Page 358
18.4 Operation of semiconductor-based optical antennas......Page 360
18.5 Semiconductor antennas for information technology and energy harvesting......Page 362
18.6 Conclusions and outlook......Page 364
Acknowledgments......Page 365
19.1 Introduction......Page 366
19.2.1 Bulk sensitivity......Page 368
Substrate effects......Page 370
19.2.2 Molecular sensing......Page 373
Relating resonance shifts to the number of adsorbed molecules......Page 374
Direct comparison between sensing platforms......Page 375
Ensemble and single particle assays......Page 376
19.3.1 Fano resonances......Page 377
19.3.2 Alternative sensing schemes......Page 379
19.3.4 Plasmonic sensing for materials science......Page 380
19.4 Conclusions and outlook......Page 381
20.1 Introduction......Page 382
20.2 The diffraction limit and spatial resolution......Page 383
20.3 Evanescent waves and metals......Page 384
20.3.2 Optical antennas......Page 385
20.4 Tip-enhanced Raman spectroscopy......Page 386
20.4.1 Spatial resolution in TERS......Page 388
20.4.2 Imaging intrinsic properties through TERS......Page 389
20.5.1 Combining optical antennas with mechanical effects......Page 390
20.6 Optical antennas as nanolenses......Page 392
20.7 Conclusions and outlook......Page 393
21.1 Introduction......Page 395
21.2.1 Single apertures......Page 396
21.2.2 Single apertures surrounded by surface corrugations......Page 398
21.2.3 Aperture arrays......Page 400
Single molecule fluorescence spectroscopy in liquids......Page 402
Live cell membrane investigations......Page 404
Trapping......Page 405
Surface plasmon resonance spectroscopy......Page 406
Surface-enhanced Raman spectroscopy......Page 408
21.4.2 Nanosources......Page 409
Acknowledgments......Page 411
References......Page 413
Index......Page 472