天線為一種可提高電磁波發射或收集效率的發明。當天線的尺寸小至數百奈米時，其工作頻率可以提升至可見光頻率。可見光電漿奈米天線是近年來科學家積極研究的題目之一，因為它除了提供了機會讓光子取代一般電子做訊號的運算，亦可以在奈米尺寸下增強可見光與物質的作用。如同一般無線電波天線，奈米電漿天線的光學響應與其結構的設計息息相關。在不同光學應用時其所需要的條件皆不同，因此奈米電漿天線的設計是一門重要的研究課題。在此論文中，我們結合理論計算以及光學實驗探討兩種電漿奈米結構的光學特性，同時也研究其具潛力的光學應用。
此論文的第一個研究主題為“電漿都普勒光柵之光學性質解析與環境折射率感測”。電漿都普勒光柵是一個二維的電漿光柵結構，其設計在水平面上呈都普勒效應波前的條紋，因此其光柵周期以及光學響應皆隨著不同方位角而做改變。在論文中，我們詳細探討電漿都普勒光柵的設計原理，同時建構出其光學響應的數學模型。在這之後，我們利用暗場散射光譜技術研究電漿都普勒光柵的光學性質，並且展示其在可見光頻率之篩選，環境折射率感測以及表面增強拉曼光譜上的應用。
此論文的第二個研究主題為“自發光驅動金奈米八木光天線：寬頻指向性奈米可見光源”。在此研究題目中，我們展示如何利用金的螢光自發光來驅動指向性奈米天線，突破一般奈米天線需要以外來螢光光源驅動的限制。利用螢光光譜技術及後焦平面影像技術，我們研究四種不同的金奈米天線螢光自發光的波長與指向性，分別為奈米粒子，奈米八木天線，L型八木奈米天線以及對數週期奈米天線。由於受到電漿共振模態的調控，螢光自發光的波段會隨著天線的共振而做位移，因此它十分適合用來驅動八木天線。利用此光學特性，我們製作出分別可往單方向輻射出650 nm, 800 nm 和 850 nm波長螢光自發光的奈米八目天線。除此之外，我們也首次成功藉由寬頻的螢光自發光驅動對數週期奈米天線。實驗結果顯示，電漿奈米天線除了可以引導電磁波外，天線本身的元件同時也是發光光源。

Inspired by radio-frequency antenna technology, engineering of plasmonic nanoantenna has gain considerable interests in recent years since it provides the opportunities to manipulate the interaction of high-frequency electromagnetic (EM) wave and matter at nanoscale. In this thesis, we present two topic regarding to the control of light and matter interaction using plasmonic nanoantennas.
In the first topic, we present a new design of two dimensional grating with continuous azimuthal angle-dependent periodicity for broadband surface plasmon wave excitation. The Plasmonic Doppler Grating (PDG) consists of a set of non-concentric circular rings that mimics the wavefronts of a moving point source and, therefore, presents azimuthal angle-resolved grating periodicity. The center and span of the working frequency window are fully designable for optimal performance in specific applications. We detail the design, fabrication and optical characterization of the PDG and demonstrate its exemplary applications in azimuthal angle-resolved color sorting, index sensing and surface-enhanced Raman scattering (SERS). We show that broadband source can be sorted continuously into surface plasmons and the variation in surrounding index can be reported as the change of in-plane angle distribution of color. Applications of PDG in grating couplers for silicon photonic circuits, hydrogen sensing, surface plasmon-enhanced spectroscopy and non-linear signal generation are anticipated.
In the second topic, we investigate the driving of directional optical nanoantennas via continuum photoluminescence emission from the gold nanostructures upon laser excitation. By employing photoluminescence (PL) spectroscopy and back-focal plane imaging technique, we study the PL emission wavelength and directivity of four different type gold nanoantennas, which is nanorods, Yagi-Uda (YU) nanoantenna, L-shape Yagi-Uda nanoantenna and log-periodic dipole nanoantenna. We show that the PL emission band always match with the operating wavelength of nanoantennas upon modulation of localized surface plasmon resonance modes, therefore rendering the driving of nanoantenna practical. For example, we shows that three different Yagi-Uda nanoantennas can launch the PL with 650 nm, 800 nm and 850 nm wavelength respectively to a single direction without placing any external quantum emitter near the feed element. Consequently, the PL emission also allow us to experimentally investigate the directivity of broadband log-periodic dipole nanoantenna for the first time. In comparison with the radio-frequency antennas, our results show that the element of optical nanoantennas not only can act as a resonator but also can be a local broadband light source. The PL of gold nanoantennas is an ideal nanoscale unidirectional light source that can be applied in wide field such as high-bandwidth wireless optical communication.

中文摘要 i
Abstract iii
Acknowledgement v
Table of Contents vi
List of Figures ix
Chapter 1 Introduction 1
Chapter 2 Principle of plasmonic optics 2
2.1 Maxwell’s equations and electromagnetic wave propagation 2
2.2 Surface plasmon wave 4
2.3 Dispersion relation of light 8
2.4 Excitation of surface plasmon wave via grating structure 9
2.5 Localized surface plasmon resonance 11
Chapter 3 Fabrication of nanoantenna 13
3.1 Numerical simulation 13
3.2 Nanostructure fabrication 14
3.3 Synthesis of single-crystalline gold flakes 15
3.3.1 Hundreds nanometer-thick single-crystalline gold flakes 15
3.3.2 Micrometer-thick single-crystalline gold flakes 17
Chapter 4 Plasmonic Doppler grating 19
4.1 Applications of plasmonic grating and its challenges 19
4.2 Design and features of Plasmonic Doppler Grating 20
4.3 Analytical model 22
4.4 Characterization methods for PDG 25
4.5 Characterization of PDG using dark field scattering microscopy 27
4.6 Application for color sorting 32
4.7 Application for angle-resolved index sensing 35
4.7.1 Detection of refractive index changes over large index range 36
4.7.2 Detection of refractive index changes over small index range 40
4.8 Application for surface-enhanced Raman scattering 42
4.8.1 Motivation 42
4.8.2 Measurement of SERS on PDG 43
4.8.3 The SERS and photoluminescence mapping on PDG 45
Chapter 5 Photoluminescence driven gold optical Yagi-Uda nanoantenna 48
5.1 Directing light at nanoscale 48
5.2 Yagi-Uda antenna 49
5.3 Driving source of optical Yagi-Uda nanoantenna 50
5.4 Motivation of photoluminescence driven nanoantenna 52
5.5 Characterizing the angular radiation pattern of a nanoantenna 54
5.6 Optical setup for spectral and directivity analysis of nanoantenna 56
5.7 Characterizing the photoluminescence of gold nanoparticles 58
5.7.1 Role of surface plasmon on PL emission band 58
5.7.2 Polarization and directivity modulation of PL in gold nanoparticles 59
5.8 Photoluminescence driven Yagi-Uda nanoantennas 61
5.9 Photoluminescence driven L-shape Yagi-Uda nanoantenna 67
5.10 Photoluminescence driven log-periodic dipole nanoantenna 69
Chapter 6 Summary and Outlook 73
References 75
Appendix 78
A1. Reflection image analysis of PDG 78
A2. Reflection intensity profile fitting 79

1. Yeh WH & Hillier AC (2013) Use of Dispersion Imaging for Grating-coupled Surface Plasmon Resonance Sensing of Multilayer Langmuir-Blodgett Films. Anal Chem 85(8):4080-4086.
2. Stockman MI, Schatz GC, McMahon JM, & Gray SK (2007) Tailoring the Parameters of Nanohole Arrays in Gold Films for Sensing Applications. 6641:664103-664103-664108.
3. CarlWadell, Syrenova S, & Langhammer C (2014) Plasmonic Hydrogen Sensing with Nanostructured Metal Hydrides. ACS Nano 8.
4. Tittl A, et al. (2011) Palladium-based Plasmonic Perfect Absorber in the Visible Wavelength Range and Its Application to Hydrogen Sensing. Nano Lett. 11(10):4366-4369.
5. Gupta R, Sagade AA, & Kulkarni GU (2012) A Low Cost Optical Hydrogen Sensing Device Using Nanocrystalline Pd Grating. Int. J. Hydrogen Energy 37(11):9443-9449.
6. Willets KA & Van Duyne RP (2007) Localized surface plasmon resonance spectroscopy and sensing. Annu Rev Phys Chem 58:267-297.
7. Liu WL, et al. (2013) The influence of shell thickness of Au@TiO2 core-shell nanoparticles on the plasmonic enhancement effect in dye-sensitized solar cells. Nanoscale 5(17):7953-7962.
8. Andrade GFS, Min Q, Gordon R, & Brolo AG (2012) Surface-Enhanced Resonance Raman Scattering on Gold Concentric Rings: Polarization Dependence and Intensity Fluctuations. J Phys Chem C 116(4):2672-2676.
9. Aouani H, et al. (2011) Bright Unidirectional Fluorescence Emission of Molecules in a Nanoaperture with Plasmonic Corrugations. Nano Lett 11(2):637-644.
10. Tsai WY, Huang JS, & Huang CB (2014) Selective trapping or rotation of isotropic dielectric microparticles by optical near field in a plasmonic archimedes spiral. Nano Lett 14(2):547-552.
11. Wang CY, et al. (2015) Giant colloidal silver crystals for low-loss linear and nonlinear plasmonics. Nat Commun 6:7734.
12. Lu YJ, et al. (2012) Plasmonic Nanolaser Using Epitaxially Grown Silver Film. Science 337:450-453.
13. Biagioni P, Huang JS, & Hecht B (2012) Nanoantennas for visible and infrared radiation. Rep Prog Phys 75(2):024402.
14. Murata K & Tanaka H (2010) Surface-wetting effects on the liquid-liquid transition of a single-component molecular liquid. Nat Commun 1:16.
15. Kretschmann E & Raether H (1968) Radiative Decay of Non Radiative Surface Plasmon Excited by Light. Z Naturforsch A 23a:2135-2136.
16. Otto A (1968) Excitation of Nonradiative Surface Plasma Waves in Silver by the Method of Frustrated Total Reflection. Z Phys 216:398-410.
17. Ebbesen TW, Lezec HJ, Ghaemi HF, Thio T, & A.Wolff P (1998) Extraordinary Optical Transmission through Sub-wavelength Hole Arrays. Nature 391:667-669.
18. Barnes WL, Dereux A, & Ebbesen TW (2003) Surface Plasmon Subwavelength Optics. Nature 424(6950):824-830.
19. Renger J, Quidant R, van Hulst N, Palomba S, & Novotny L (2009) Free-Space Excitation of Propagating Surface Plasmon Polaritons by Nonlinear Four-Wave Mixing. Phys Rev Lett 103(26):266802.
20. Li J, Guo H, & Li Z-Y (2013) Microscopic and macroscopic manipulation of gold nanorod and its hybrid nanostructures. Photonics Research 1(1):28.
21. Chen WL, et al. (2014) The Modulation Effect of Transverse, Antibonding, and Higher-Order Longitudinal Modes on the Two-Photon Photoluminescence of Gold Plasmonic Nanoantennas. ACS Nano 8:9053-9062.
22. Huang JS, et al. (2010) Atomically flat single-crystalline gold nanostructures for plasmonic nanocircuitry. Nat Commun 1(150).
23. Kollmann H, et al. (2014) Toward plasmonics with nanometer precision: nonlinear optics of helium-ion milled gold nanoantennas. Nano Lett 14(8):4778-4784.
24. Laux E, Genet C, Skauli T, & Ebbesen TW (2008) Plasmonic Photon Sorters for Spectral and Polarimetric Imaging. Nat Photon 2(3):161-164.
25. Lee KL, et al. (2012) Enhancing Surface Plasmon Detection Using Template-Stripped Gold Nanoslit Arrays on Plastic Films. ACS Nano 6:2931-2939.
26. Zeng B, Gao Y, & Bartoli FJ (2013) Ultrathin Nanostructured Metals for Highly transmissive Plasmonic Subtractive Color Filters. Sci Rep 3:2840.
27. Xu T, Wu YK, Luo X, & Guo LJ (2010) Plasmonic Nanoresonators for High-resolution Colour Filtering and Spectral Imaging. Nat Commun 1:59.
28. Lin D & Huang JS (2014) Slant-gap Plasmonic Nanoantennas for Optical Chirality Engineering and Circular Dichroism Enhancement. Opt Express 22(7):7434-7445.
29. Sobhani A, et al. (2013) Narrowband Photodetection in the Near-infrared with a Plasmon-induced Hot Electron Device. Nat Commun 4:1643.
30. Zheng BY, Wang Y, Nordlander P, & Halas NJ (2014) Color-selective and CMOS-compatible Photodetection Based on Aluminum Plasmonics. Adv Mater 26(36):6318-6323.
31. García-Vidal FJ & Martín-Moreno L (2002) Transmission and Focusing of Light in One-dimensional Periodically Nanostructured Metals. Phys. Rev. B 66(15).
32. Fu Y, et al. (2012) All-optical Logic Gates Based on Nanoscale Plasmonic Slot Waveguides. Nano Lett 12(11):5784-5790.
33. Lu C, et al. (2014) Multi-color Photon Sorting in Plasmonic Microcavities. J. Opt. 16(1):015003.
34. Koohyar F, Kiani F, Sharifi S, Sharifirad M, & Rahmanpour SH (2012) Study on the Change of Refractive Index on Mixing, Excess Molar Volume and Viscosity Deviation for Aqueous Solution of Methanol, Ethanol, Ethylene Glycol, 1-Propanol and 1, 2, 3-Propantriol at T = 292.15 K and Atmospheric Pressure. Res J App Sci Eng Technol 4:3095-3101.
35. Curto AG, et al. (2010) Unidirectional Emission of a Quantum Dot Coupled to a Nanoantenna. Science:930-932.
36. Curto AG, et al. (2013) Multipolar radiation of quantum emitters with nanowire optical antennas. Nat Commun 4:1750.
37. Hancu IM, Curto AG, Castro-Lopez M, Kuttge M, & van Hulst NF (2014) Multipolar interference for directed light emission. Nano Lett 14(1):166-171.
38. Zhu W, Wang D, & Crozier KB (2012) Direct observation of beamed Raman scattering. Nano Lett 12(12):6235-6243.
39. Ramezani M, et al. (2015) Hybrid Semiconductor Nanowire-Metallic Yagi-Uda Antennas. Nano Lett 15(8):4889-4895.
40. Coenen T, Vesseur EJ, Polman A, & Koenderink AF (2011) Directional emission from plasmonic Yagi-Uda antennas probed by angle-resolved cathodoluminescence spectroscopy. Nano Lett 11(9):3779-3784.
41. Beversluis MR, Bouhelier A, & Novotny L (2003) Continuum generation from single gold nanostructures through near-field mediated intraband transitions. Phy Rev B 68(11).
42. Yorulmaz M, Khatua S, Zijlstra P, Gaiduk A, & Orrit M (2012) Luminescence quantum yield of single gold nanorods. Nano Lett 12(8):4385-4391.
43. Huang D, et al. (2015) Photoluminescence of a Plasmonic Molecule. ACS Nano 7:7072-7079.
44. Jiang LJ, et al. (2015) Probing Vertical and Horizontal Plasmonic Resonant States in the Photoluminescence of Gold Nanodisks. ACS Photonics 2(8):1217-1223.
45. Hu H, Duan H, Yang YKS, & Shen ZX (2012) Plasmon-Modulated Photoluminescence of Individual Gold Nanostructures. ACS Nano 6:10147-10155.
46. Sheppard CJR & Matthews HJ (1993) Imaging in high-aperture optical systems. J. Mod. Opt. 40:1631.
47. Li J, Salandrino A, & Engheta N (2009) Optical spectrometer at the nanoscale using optical Yagi-Uda nanoantennas. Physical Review B 79(19).
48. Maksymov IS, et al. (2012) Multifrequency tapered plasmonic nanoantennas. Optics Communications 285(5):821-824.
49. Pavlov RS, Curto AG, & van Hulst NF (2012) Log-periodic optical antennas with broadband directivity. Optics Communications 285(16):3334-3340.
50. Miroshnichenko AE, et al. (2011) An arrayed nanoantenna for broadband light emission and detection. physica status solidi (RRL) - Rapid Research Letters 5(9):347-349.
51. Kao TS, Chen YG, & Hong MH (2013) Controlling the near-field excitation of nano-antennas with phase-change materials. Beilstein J Nanotechnol 4:632-637.