兆赫波間隙（即電磁波頻率在0.1至30兆赫頻段）的研究在近年來受到大家關注，因為兆赫波間隙處於微波與遠紅外線的交界處，也是傳統電子響應到光學響應的分水嶺，因此自然界的物質在兆赫波間隙頻段的電子跟光學響應都相當微弱，使兆赫波頻段訊號的產生與偵測相當困難;有鑒於此，我們利用超材料在微波與紅外線頻段甚至到可見光頻段的成熟發展及超材料本身工作頻段的可調性，將具有強烈電子與光學響應的超材料應用到兆赫波間隙，希望能改善兆赫波間隙貧乏的光學應用。
　　在此篇論文中，我們探討三種不同在兆赫波間隙的可能應用。第一個研究是藉由旋轉平面隙環共振器設計出三維的負折射率超材料。我們利用一個簡單且單一的半圓金屬球殼，即可同時擁有磁共振及電共振進而產生負折射現象，使得製程方面的可行性提高。更由於較高的對稱性，該結構不受入射光極化方向影響，並且對電磁波入射角度依賴性較低，使得在實際應用上有較大的優勢。延伸磁共振與電共振的應用，在第二個研究中我們調控磁共振及電共振發生的頻段，使得導磁係數以及介電常數在特定頻率下相交，讓該元件的阻抗跟真空相近使反射降低，而超材料共振的特性能提高折射率的虛部而降低穿透。當反射及穿透同時逼近零時即可得到完美吸收。此外，我們利用隨機產生圖形方法設計擁有次波長厚度的金屬-介電質-金屬的三明治結構並使其擁有雙面吸收的特性，解決了傳統吸收體只能單面吸收的缺點，此微型雙面吸收體將在元件整合上擁有更大的利基。接下來，我們思考是否能從隨機方法中找出有效率地優化超材料表現的方式，因此我們選用基因演算法來對既有的超材料優化，由於全部最佳化過程皆由電腦程式控制，因此能有系統性地找出所需的超材料圖形而不需使用試誤法，此法可大幅增加研究的效率。此研究中，我們選用了在未來兆赫波通訊中重要的「帶通濾波器」元件來當成我們的目標，藉由基因演算法，我們得到最佳化的超材料超寬頻帶通濾波器並具有82.2%頻寬及58.3分貝每八度的邊界轉換效率，而且該濾波器僅僅只有38微米的厚度，因此我們所提出的兆赫波頻段微型化超寬頻濾波器對於兆赫波的光學系統有相當程度上的幫助。
　　最後，此篇論文總結我們致力發展的三種不同兆赫波元件:一、不受極化方向影響及高入射角容忍度的三維負折射超材料，二、利用隨機方法產生的雙面完美吸收體以及三、有效最佳化的超材料超寬頻帶通波器。這些應用驗證了超材料其獨特的光學特性，而我們設計出的各式兆赫波元件將對兆赫波間隙的應用造成重大影響。

The researches on THz gap (0.1-30 THz) have attracted much attention in recent years because the THz gap is a transition regime between microwave and far-infrared (IR), i.e., the watershed between the electronic and optical responses so that matters in THz gap in nature possess weak electronic and optical responses, and such weak responses hinder generation and detection of THz signals. Therefore, we eager to apply metamaterials to THz devices based on the properties of metamaterials that is well developed in microwave, IR and even visible region such as their scalability and strong interaction with waves; based on these properties, we expect to expand the applications in the THz gap.
In this dissertation, we delve into three different applications at the THz gap. The first research topic is to construct a three-dimensional (3D) negative index medium (NIM) through rotating a split ring resonator. Such 3D NIM, unlike traditional NIM integrating two independent magnetic and electric resonators together, achieves electric and magnetic responses simultaneously and also negative index via a monolithic structure, that is, a metallic hemispherical shell; the shell could simplify the fabrication process of 3D NIM. Furthermore, this monolithic shell is independent of polarization and insensitive to incident angles due to its high symmetry that are favorable in practical applications. Next, in the second project, we modulate the frequencies of magnetic and electric resonances so that permeability and permittivity of the metamaterial intersect with each other to match the impedance of free space, thus leading to suppression of reflectance. On the other hand, via the resonance nature of metamaterials, the imaginary part of index is enhanced when resonance occurred, so transmittance is reduced. While reflectance and transmittance of a material are simultaneously approaching to zero, a perfect absorber could be achieved. Hence, in this topic, we employed stochastic design process to generate a double-sided metamaterial perfect absorber that is composed of a dielectric layer sandwiched by two identical metallic patterns and could absorb the electromagnetic wave from two sides, solving the drawback of traditional metamaterial absorbers, i.e., single operating direction. Noteworthily, such perfect absorber owns a sub-wavelength thickness, thus miniaturizing the devices and providing a promising future compared to conventional absorbers. Afterward, based on the previous stochastic design process, we consider increasing the efficiency of the design process of metamaterials with desired goals. Consequently, in the third project, instead of trial and error process, we utilize computer-aided genetic algorithms (GAs) to efficiently optimize the existing metamaterials and come out the best metamaterial patterns. A bandpass filter, an important unit on future THz communications, is chosen as our target to execute GA and then approach behaviors of ultra-broad fractional bandwidth 82.8% and band-edge transition of 58.3 dB/octave. Besides, the 38-μm-thick and optimized bandpass filter, which is much thinner compared to conventional THz filter. Such miniaturized ultra-broadband and sharp-transition filters profit the development of a THz optical system.
To summarize, in this dissertation, we devote ourselves into three different THz devices including 1. Polarization independent and high incident-angle tolerable 3D negative index media, 2. Stochastically designed double-sided perfect absorbers and finally 3. Ultra-broad bandwidth and sharp transition metamaterial THz bandpass filters via genetic algorithm. Such devices validate the exotic properties of metamaterials and would have a huge impact on the field of the THz gap.

1. V. Veslago, “The Electrodynamics of Substances with Simultaneously Negative Values of  and ,” Sov. Phys. Uspekhi. 10, 509 (1968).
2. J. B. Pendry, A. J. Holden, D. J. Robbins, and W. J. Stewart, “Magnetism from Conductors and Enhanced Nonlinear Phenomena,” IEEE T. Microw. Theory 47(11), 2075 (1999).
3. T. J. Yen, W. J. Padilla, N. Fang, D. C. Vier, D. R. Smith, J. B. Pendry, D. N. Basov, and X. Zhang, “Terahertz Magnetic Response from Artificial Materials,” Science 303, 1494 (2004).
4. S. Linden, C. Enkrich, M. Wegener, J. F. Zhou, Th. Koschny, and C. M. Soukoulis, “Magnetic Response of Metamaterials at 100 Terahertz,” Science 306, 1351 (2004).
5. C. Enkrich, M. Wegener, S. Linden, S. Burger, L. Zschiedrich, F. Schmidt, J. F. Zhou, Th. Koschny, and C. M. Soukoulis, “Magnetic Metamaterials at Telecommunication and Visible Frequencies,” Phys. Rev. Lett. 95, 253901 (2005).
6. J. B. Pendry, A. J. Holden, W. J. Stewart, and I. Youngs, “Extremely Low Frequency Plasmons in Metallic Mesostructures,” Phys. Rev. Lett. 76(25), 4773 (1996).
7. R. A. Shelby, D. R. Smith, and S. Schultz, “Experimental Verification of a Negative Index of Refraction,” Science 292, 77 (2001).
8. J. B. Pendry, “Negative Refraction Makes a Perfect Lens,” Phys. Rev. Lett. 85, 3966 (2000).
9. K. L. Tsakmakidis, A. D. Boardman, and O. Hess, “‘Trapped Rainbow’ Storage of Light in Metamaterials,” Nature 450, 397 (2007).
10. T. Y. Huang, T. C. Yang, and T. J. Yen, “Slowing Light by Exciting the Fundamental Degeneracy Oscillatory Mode in a Negative Refractive Waveguide,” Appl. Phys. Lett. 102, 111102 (2013).
11. Y. Avitzour, Y. A. Urzhumov, and G. Shvets, “Wide-angle Infrared Absorber Based on a Negative-index Plasmonic Metamaterial,” Phys. Rev. B 79, 045131 (2009).
12. Y. Lai, H. Y. Chen, Z. Q. Zhang, and C. T. Chan, “Complementary Media Invisibility Cloak that Cloaks Objects at a Distance Outside the Cloaking Shell,” Phys. Rev. Lett. 102, 093901 (2009).
13. Z. W. Liu, H. S. Lee, Y. Xiong, C. Sun, X. Zhang, “Far-Field Optical Hyperlens Magnifying Sub-diffraction-limited Objects,” Science 315, 1686 (2007).
14. Y. J. Chiang and T. J. Yen, “A Composite-metamaterial-based Terahertz-wave Polarization Rotator with an Ultrathin Thickness, an Excellent Conversion Ratio, and Enhanced Transmission,” Appl. Phys. Lett. 102, 011129 (2013).
15. M. Diem, Th. Koschny, and C. M. Soukoulis, “Wide-angle Perfect Absorber/ Thermal emitter in the Terahertz Regime,” Phys. Rev. B 79, 033101 (2009).
16. Y. C. Lai , H. C. Lee , S. W. Kuo , C. K. Chen , H. T. Wu, O. K. Lee , and T. J. Yen, “Label-Free, Coupler-Free, Scalable and Intracellular Bio-imaging by Multimode Plasmonic Resonances in Split-Ring Resonators,” Adv. Mater. 24, 148(2012).
17. C. Sirtori, “Bridge for the Terahertz Gap,” Nature 417, 132 (2002).
18. G. P. Williams, “Filling the THz Gap—High Power Sources and Applications,” Rep. Prog. Phys. 69, 301 (2006).
19. A. G. Davies, A. D. Burnett, W. H. Fan, E. H. Linfield, and J. E. Cunningham, “Terahertz Spectroscopy of Explosives and Drugs,” Mater. Today 11, 3 (2008).
20. B. Zhu, Y. Chen, K. Deng, W. Hu, and Z. S. Yao, “Terahertz Science and Technology and Applications,” Pr. Electromagn. Res. S. Proceedings Beijing, China, March 23-27, 1166 (2009).
21. M. Shur, “Terahertz Technology: Devices and Applications,” Proc. Eur. S-State Dev., 13 (2005).
22. Y. J. Chiang, C. S. Yang, Y. H. Yang, C. L. Pan, and T. J. Yen, “An Ultrabroad Terahertz Bandpass Filter Based on Multiple-resonance Excitation of a Composite Metamaterial,” Appl. Phys. Lett. 99, 191909 (2011).
23. T. Driscoll, G. O. Andreev, D. N. Basov, S. Palit, S. Y. Cho, N. M. Jokerst, and D. R. Smith, “Tuned Permeability in Terahertz Split-ring Resonators for Devices and Sensors,” Appl. Phys. Lett. 91, 062511 (2007).
24. B. Ferguson, and X. C. Zhang, “Materials for Terahertz Science and Technology,” Nature 1, 26 (2002).
25. D. R. Smith, W. J. Padilla, D. C. Vier, S. C. Nemat-Nasser, and S. Schultz, “Composite Medium with Simultaneously Negative Permeability and Permittivity,” Phys. Rev. Lett. 84(18), 4184 (2000).
26. R. A. Shelby, D. R. Smith, S. C. Nemat-Nasser, and S. Schultz, “Microwave Transmission through a Two-dimensional, Isotropic, Left-handed Metamaterial,” Appl. Phys. Lett. 78, 489 (2001).
27. M. Bayindir, K. Aydin, and E. Ozbay, “Transmission Properties of Composite Metamaterials in Free Space,” Appl. Phys. Lett. 81, 120 (2002).
28. C. G. Parazzoli, R. B. Greegor, K. Li, B. E. C. Koltenbah, and M. Tanielian, “Experimental Verification and Simulation of Negative Index of Refraction Using Snell’s Law” Phys. Rev. Lett. 90, 107401 (2003).
29. G. Dolling, C. Enkrich, M. Wegener, J. F. Zhou, C. M. Soukoulis, and S. Linden, “Cut-wire Pairs and Plate Pairs as Magnetic Atoms for Optical Metamaterials,” Opt. Lett. 30, 3198 (2005).
30. S. Zhang, W. J. Fan, N. C. Panoiu, K. J. Malloy, R. M. Osgood, and S. R. J. Brueck, “Experimental Demonstration of Near-infrared Negative-index Metamaterials,” Phys. Rev. Lett. 95, 137404 (2005).
31. K. Aydin, Z. F. Li, L. Sahin, and E. Ozbay, “Negative Phase Advance in Polarization Independent, Multi-layer Negative-index Metamaterials,” Opt. Express 16, 8835 (2008).
32. G. Dolling, C. Enkrich, M. Wegener, C. M. Soukoulis, and S. Linden, “Low-loss Negative-index Metamaterial at Telecommunication Wavelengths,” Opt. Lett. 31, 1800 (2006).
33. G. Dolling, C. Enkrich, and M. Wegener, C. M. Soukoulis, and S. Linden, “Negative-index Metamaterial at 780 nm Wavelength,” Opt. Lett. 32, 53 (2007).
34. J. F. Zhou, L. Zhang, G. Tuttle, Th. Koschny, and C. M. Soukoulis, “Negative Index Materials Using Simple Short Wire Pairs,” Phys. Rev. B 73, 041101(R) (2006).
35. V. M. Shalaev, W. S. Cai, U. K. Chettiar, H. K. Yuan, A. K. Sarychev, V. P. Drachev, and A. V. Kildishev, “Negative Index of Refraction in Optical Metamaterials,” Opt. Lett. 30, 3356 (2005).
36. O. Paul1, C. Imhof, B. Reinhard, R. Zengerle, and R. Beigang, “Negative Index Bulk Metamaterial at Terahertz Frequencies,” Opt. Express 16, 6736 (2008).
37. M. Kafesaki, I. Tsiapa, N. Katsarakis, Th. Koschny, C. M. Soukoulis, and E. N. Economou, “Left-handed Metamaterials: The Fishnet Structure and Its Variations,” Phys. Rev. B 75, 235114 (2007).
38. J. Valentine, S. Zhang, Th. Zentgraf, E. Ulin-Avila, D. A. Genov, G. Bartal, and X. Zhang, “Three-dimensional Optical Metamaterial with a Negative Refractive Index,” Nature 455, 376 (2008).
39. D. Chanda, K. Shigeta, S. Gupta, T. Cain, A. Carlson, A. Mihi, A. J. Baca, G. R. Bogart, P. Braun, and J. A. Rogers, “Large-area Flexible 3D Optical Negative Index Metamaterial Formed by Nanotransfer Printing,” Nat. Nanotechnol. 6, 402 (2011).
40. Th. Koschny, L. Zhang, and C. M. Soukoulis, “Isotropic Three-dimensional Left-handed Metamaterials,” Phys. Rev. B 71, 121103(R) (2005).
41. B. Y. Gong, and X. P. Zhao, “Three-dimensional Isotropic Metamaterial Consisting of Domain-structure,” Physica B 407, 1034 (2012).
42. R. Paniagua-Domínguez, F. López-Tejeira, R. Marqués, and J. A. Sánchez-Gil, “Metallo-dielectric Core–shell Nanospheres as Building Blocks for Optical Three-dimensional Isotropic Negative-index Metamaterials,” New J. Phys. 13, 123017 (2011).
43. X. Zhang and Z. W. Liu, “Superlenses to Overcome the Diffraction Limit,” Nat. Mater. 7, 435 (2008).
44. J. L. He, J. Yi, and S. L. He, “Giant Negative Goos-Hänchen Shifts for a Photonic Crystal with a Negative Effective Index,” Opt. Express 14, 3024 (2006).
45. W. W. Salisbury, “Absorbed Body of Electronic Waves,” U.S. Patent No. 2, 599, 944 (1952).
46. B. Chambers, “Optimum Design of a Salisbury Screen Radar Absorber,” Electron. Lett. 30, 1353 (1994).
47. W. H. Emerson, “Electromagnetic Wave Absorbers and Anechoic Through the Years,” IEEE T. Antenn. Propag. AP-21, 484 (1973).
48. E. F. Knott, and C. D. Lunden, “The Two-Sheet Capacitive Jaumann Absorber,” IEEE T. Antenn. Propag. 43, 1339 (1995).
49. N. I. Landy, S. Sajuyigbe, J. J. Mock, D. R. Smith, and W. J. Padilla, “Perfect Metamaterial Absorber,” Phys. Rev. Lett. 100, 207402 (2008).
50. X. L. Liu, T. Starr, A. F. Starr, and W. J. Padilla, “Infrared Spatial and Frequency Selective Metamaterial with Near-Unity Absorbance,” Phys. Rev. Lett. 104, 207403 (2010).
51. Q. Y. Wen, H. W. Zhang, Y. S. Xie, Q. H. Yang, and Y. L Liu, “Dual Band Terahertz Metamaterial Absorber: Design, Fabrication, and Characterization,” Appl. Phys. Lett. 95, 241111 (2009).
52. J. B. Sun, L. Y. Liu, G. Y. Dong, and J. Zhou, “An Extremely Broad Band Metamaterial Absorber Based on Destructive Interference,” Opt. Express 19, 21155 (2011).
53. J. Grant, Y. Ma, S. Saha, L. B. Lok, A. Khalid, and D. R. S. Cumming, “Polarization Insensitive Terahertz Metamaterial Absorber,” Opt. Express 36, 1524 (2011).
54. M. B. Pu, C. G. Hu, M. Wang, C. Huang, Z. Y. Zhao, C. T. Wang, Q. Feng, and X. G. Luo, “Design Principles for Infrared Wide-angle Perfect Absorber Based on Plasmonic Structure,” Opt. Express 19, 17413 (2011).
55. N. Liu, M. Mesch, Th. Weiss, M. Hentschel, and H. Giessen, “Infrared Perfect Absorber and Its Application as Plasmonic Sensor,” Nano Lett. 10, 2342 (2010).
56. S. A. Kuznetsov, A. G. Paulish, A. V. Gelfand, P. A. Lazorskiy, and V. N. Fedorinin, “Matrix Structure of Metamaterial Absorbers for Multispectral Terahertz Imaging,” Prog. Electromagn. Res. 122, 93 (2012).
57. C. M. Watts , X. L. Liu , and W. J. Padilla, “Metamaterial Electromagnetic Wave Absorbers,” Adv. Mater. 24, OP98 (2012).
58. K. Iwaszczuk, A.C. Strikwerda, K. B. Fan, X. Zhang, R. D. Averitt, and P. U. Jepsen, “Flexible Metamaterial Absorbers for Stealth Applications at Terahertz Frequencies,” Opt. Express 20, 635 (2012).
59. H. Wang, V. P. Sivan, A. Mitchell, G. Rosengarten, P. Phelan, and L. P. Wang, “Highly Efficient Selective Metamaterial Absorber for High-temperature Solar Thermal Energy Harvesting,” Sol. Energ. Mat. Sol. C. 137, 235 (2015).
60. J. S. Hong, “Microstrip Filters for RF / Microwaves Applications (2nd edi.),” New York: John Wiley & Sons, Inc. (2011).
61. F. Falcone, T. Lopetegi, M. A. G. Laso, J. D. Baena, J. Bonache, M. Beruete, R. Marqués, F. Martín, and M. Sorolla, “Babinet Principle Applied to the Design of Metasurfaces and Metamaterials,” Phys. Rev. Lett. 93, 197401 (2004).
62. A. M. Melo, M. A. Kornberg, P. Kaufmann, M. H. Piazzetta, E. C. Bortolucci, M. B. Zakia, O. H. Bauer, A. Poglitsch, and A. M. P. Alves da Silva, “Metal Mesh Resonant Filters for Terahertz Frequencies,” Appl. Optics 47, 6064 (2008).
63. H. R. Park, Y. M. Park, H. S. Kim, J. S. Kyoung, M. A. Seo, D. J. Park, Y. H. Ahn, K. J. Ahn, and D. S. Kim, “Terahertz Nanoresonators: Giant Field Enhancement and Ultrabroadband Performance,” Appl. Phys. Lett. 96, 121106 (2010).
64. H. Bahrami and M. Hakkak, “Analysis and Design of Highly Compact Bandpass Waveguide Filter Utilizing Complementary Split Ring Resonators (CSRR),” Prog. Electromagn. Res. 80, 107 (2008).
65. T. Y. Huang and T. J. Yen, “A High-ratio Bandwidth Square-wave-like Bandpass Filter by Two-handed Metamaterials and Its Application in 60GHZ Wireless Communication,” Prog. Electromagn. Res. 21, 19 (2011).
66. V. A. Fedotov, M. Rose, S. L. Prosvirnin, N. Papasimakis, and N. I. Zheludev, “Sharp Trapped-Mode Resonances in Planar Metamaterials with a Broken Structural Symmetry,” Phys. Rev. Lett. 99, 147401 (2007).
67. O. Paul, R. Beigang, and M. Rahm, “Highly Selective Terahertz Bandpass Filters Based on Trapped Mode Excitation,” Opt. Express 17, 18590 (2009).
68. M. Clemens and T. Weiland, “Discrete Electromagnetism with the Finite Integration Technique,” Prog. Electromagn. Res. 65, 19 (2001).
69. M. Silveirinha and N. Engheta, “Tunneling of Electromagnetic Energy through Subwavelength Channels and Bends using "-Near-Zero Materials,” Phys. Rev. Lett. 97, 157403 (2006).
70. A. Alù, M. G. Silveirinha, A Salandrino, and N. Engheta, “Epsilon-near-zero Metamaterials and Electromagnetic Sources: Tailoring the Radiation Phase Pattern,” Phys. Rev. B 75, 155410 (2007).
71. D. R. Smith and S. Schultz, “Determination of Effective Permittivity and Permeability of Metamaterials from Reflection and Transmission Coefficients,” Phys. Rev. B 65, 195104 (2002).
72. H. Robbins and B. Schwartz, “Chemical Etching of Silicon,” J. Electrochem. Soc. 106, 505 (1959).
73. A. A. Hamzah, N. A. Aziz, B. Y. Majlis, .J Yunas, C. F. Dee, and B. Bais, “Optimization of HNA Etching Parameters to Produce High Aspect Ratio Solid Silicon Microneedles,” J. Micromech. Microeng. 22, 095017 (2012).
74. K. B. Alici1 and E. Ozbay, “Characterization and Tilted Response of a Fishnet Metamaterial Operating at 100 GHz,” J. Phys. D: Appl. Phys. 41, 135011 (2008).
75. M. Tonouchi, “Cutting-edge Terahertz Technology,” Nat. Photonics 1, 97 (2007).
76. J. Q. Gu, J. G. Han, X. C. Lu, R. J. Singh, Z. Tian, Q. R. Xing, and W. L. Zhang, “A Close-ring Pair Terahertz Metamaterial Resonating at Normal Incidence,” Opt. Express 17, 20307 (2009).
77. J. S. Li and J. R. Li, “Dielectric Properties of Silicon in Terahertz Wave Region,” Microw. Opt. Techn. Let. 50, 1143 (2008).
78. D. R. Smith, D. C. Vier, Th. Koschny, and C. M. Soukoulis, “Electromagnetic Parameter Retrieval from Inhomogeneous Metamaterials,” Phys. Rev. E 71, 036617 (2005).
79. T. Koschny, P. Markoš, D. R. Smith, and C. M. Soukoulis, “Resonant and Antiresonant Frequency Dependence of the Effective Parameters of Metamaterials,” Phys. Rev. E 68, 065602(R) (2005).
80. J. F. Zhou, Th. Koschny, L. Zhang, G. Tuttle, and C. M. Soukoulis, “Experimental Demonstration of Negative Index of Refraction,” Appl. Phys. Lett. 88, 221103 (2006).
81. T. C. Yang, Y. H. Yang, T. J. Yen, “An Anisotropic Negative Refractive Index Medium Operated at Multiple-angle Incidences,” Opt. Express 17, 24189 (2009).
82. M. I. Aslam and D. Ö. Güney, “Dual-band, Double-negative, Polarization-independent Metamaterial for the Visible Spectrum,” J. Opt. Soc. Am. B 29, 2839 (2012).
83. C. Sabah and H. G. Roskos, “Dual-band Polarization-independent Sub-terahertz Fishnet Metamaterial,” Curr. Appl. Phys. 12, 443 (2012).
84. C. Y. Chen, S. C. Wu, and T. J. Yen, “Experimental Verification of Standing-wave Plasmonic Resonances in Split-ring resonators,” Appl. Phys. Lett. 93, 034110 (2008).
85. Y. T. Chang, Y. C. Lai, C. T. Li, C. K. Chen, and T. J. Yen, “A Multi-functional Plasmonic Biosensor.” Opt. Express 18, 9561 (2010).
86. H. Tao, N. I. Landy, C. M. Bingham, X. Zhang, R. D. Averitt, and W. J. Padilla, “A Metamaterial Absorber for the Terahertz Regime: Design, Fabrication and Characterization,” Opt. Express 16, 7181 (2008).
87. H. Wakatsuchi, S. Greedy, C. Christopoulos, and J. Paul, “Customised Broadband Metamaterial Absorbers for Arbitrary Polarisation,” Opt. Express 18, 22187 (2010).
88. K. Aydin, V. E. Ferry, R. M. Briggs, and H. A. Atwater, “Broadband Polarization-independent Resonant Light Absorption Using Ultrathin Plasmonic Super Absorbers,” Nat. Commun. 2, 517 (2011).
89. M. A. Kats, R. Blanchard, P. Genevet, and F. Capasso, “Nanometre Optical Coatings Based on Strong Interference Effects in Highly Absorbing Media,” Nat. Mater. 12, 20 (2013).
90. H. Dotan, O. Kfir, E. Sharlin, O. Blank, M. Gross, I. Dumchin, G. Ankonina, and A. Rothschild, “Resonant Light Trapping in Ultrathin Films for Water Splitting,” Nat. Mater. 12, 158 (2013).
91. N. F. Yu and F. Capasso, “Flat Optics with Designer Metasurfaces,” Nat. Mater. 13, 139 (2014).
92. E. E. Narimanov and A. V. Kildishev, “Optical Black Hole: Broadband Omnidirectional Light Absorber,” Appl. Phys. Lett. 95, 041106 (2009).
93. D. A. Genov, S. Zhang, and X. Zhang, “Mimicking Celestial Mechanics in Metamaterials,” Nat. Phys. 5, 687 (2009).
94. C. Sheng, H. Liu, Y. Wang, S. N. Zhu and D. A. Genov, “Trapping Light by Mimicking Gravitational Lensing,” Nat. Photonics 7, 902 (2007).
95. C. Imhof and R. Zengerle, “Experimental Verification of Negative Refraction in a Double Cross Metamaterial,” Appl. Phys. A-Mater. 94, 45 (2009).
96. H. T. Chen, “Interference Theory of Metamaterial Perfect Absorbers,” Opt. Express 20, 7165 (2012).
97. D. J. Kern and D. H. Werner, “A Genetic Algorithm Approach to the Design of Ultra-thin Electromagnetic Bandgap Absorbers,” Microw. Opt. Techn. Let. 38, 61 (2003).
98. P. Y. Chen, C. H. Chen, H. Wang, J. H. Tsai, and W. X. Ni, “Synthesis Design of Artificial Magnetic Metamaterials Using a Genetic Algorithm,” Opt. Express 16, 12806 (2008).
99. M. Iwanaga, “Optically Deep Asymmetric One-dimensional Plasmonic Crystal Slabs: Genetic Algorithm Approach,” J. Opt. Soc. Am. B 26, 1111 (2009).
100. H. A. Atwater and A. Polman, “Plasmonics for Improved Photovoltaic Devices,” Nat. Mater. 9, 205 (2010).
101. Y. Wang, T. Y. Sun, T. Paudel, Y. Zhang, Z. F. Ren, and K. Kempa, “Metamaterial-Plasmonic Absorber Structure for High Efficiency Amorphous Silicon Solar Cells,” Nano Lett. 12, 440 (2012).
102. F. Miyamaru, Y. Saito, M. W. Takeda, B. Hou, L. Liu, W. Wen, and P. Sheng, “Terahertz Electric Response of Fractal Metamaterial Structures,” Phys. Rev. B 77, 045124 (2008).
103. D. S. Weile and E. Michielssen, “Genetic Algorithm Optimization Applied to Electromagnetics: A Review,” IEEE T. Antenn. Propag. 45, 343 (1997).
104. T. K. Wu, “Frequency Selective Surface and Grid Array,” New York: John Wiley & Sons, Inc. (1995).
105. Ranjan Singh, C. Rockstuhl, and W. L. Zhang, “Strong Influence of Packing Density in Terahertz Metamaterials,” Appl. Phys. Lett. 97, 241108 (2010).
106. S. Genovesi1, T. J. Yen, A. Monorchio, E. Prati, Y. J. Chiang, F. Costa, “Optimization of Wide-Bandpass Filter within the Terahertz Frequency Regime,” General Assembly and Scientific Symposium, 2011 XXXth URSI (2011).
107. J. F. Zhou, E. N. Economon, Th. Koschny, and C. M. Soukoulis, “Unifying Approach to Left-handed Material Design,” Opt. Lett. 31, 3620 (2006).
108. S. T. Chase and R. D. Joseph, “Resonant Array Bandpass Filters for the Far Infrared,” Appl. Optics 22, 1775 (1983).
109. S. Zhang, W. J. Fan, K. J. Malloy and S. R. J. Brueck, “Near-infrared Double Negative Metamaterials,” Opt. Express 13, 4922 (2005).
110. N. Papasimakis, V. A. Fedotov, and N. I. Zheludev, “Metamaterial Analog of Electromagnetically Induced Transparency,” Phys. Rev. Lett. 101, 253903 (2008).