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Andreas Bayer, Marcel Pozimski, Simon Schambeck, Dieter Schuh, Rupert Huber, Dominique Bougeard, Christoph Lange
Achieving control over light-matter interaction in custom-tailored nanostructures is at the core of modern quantum electrodynamics. In strongly and ultrastrongly coupled systems, the excitation is repeatedly exchanged between a resonator and an electronic transition at a rate known as the vacuum Rabi frequency ΩR. For ΩR approaching the resonance frequency ωc, novel quantum phenomena including squeezed states, Dicke superradiant phase transitions, the collapse of the Purcell effect, and a population of the ground state with virtual photon pairs are predicted...
September 22, 2017: Nano Letters
L Velleman, L Scarabelli, D Sikdar, A A Kornyshev, L M Liz-Marzán, J B Edel
Self-assembled nanoparticle (NP) arrays at liquid interfaces provide a unique optical response which has opened the door to new tuneable metamaterials for sensing and optical applications. NPs can spontaneously assemble at a liquid-liquid interface, forming an ordered, self-healing, low-defect 2D film. The close proximity of the NPs at the interface results in collective plasmonic modes with a spectral response dependent on the distance between the NPs and induces large field enhancements within the gaps. In this study, we assembled spherical and rod-shaped gold NPs with the aim of improving our understanding of NP assembly processes at liquid interfaces, working towards finely controlling their structure and producing tailored optical and enhanced Raman signals...
September 21, 2017: Faraday Discussions
Haotian Wu, Shuo Liu, Xiang Wan, Lei Zhang, Dan Wang, Lianlin Li, Tie Jun Cui
Metamaterials are artificial structures composed of subwavelength unit cells to control electromagnetic (EM) waves. The spatial coding representation of metamaterial has the ability to describe the material in a digital way. The spatial coding metamaterials are typically constructed by unit cells that have similar shapes with fixed functionality. Here, the concept of frequency coding metamaterial is proposed, which achieves different controls of EM energy radiations with a fixed spatial coding pattern when the frequency changes...
September 2017: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Jinwei Zeng, Ting S Luk, Jie Gao, Xiaodong Yang
Miniaturized quarter-wave plate devices empower spin to orbital angular momentum conversion and vector polarization formation, which serve as bridges connecting conventional optical beam and structured light. Enabling the manipulability of additional dimensions as the complex polarization and phase of light, quarter-wave plate devices are essential for exploring a plethora of applications based on orbital angular momentum or vector polarization, such as optical sensing, holography, and communication. Here we propose and demonstrate the magnetic metamaterial quarter-wave turbines at visible wavelength to produce radially and azimuthally polarized vector vortices from circularly polarized incident beam...
September 19, 2017: Scientific Reports
Raphael Dehmel, James A Dolan, Yibei Gu, Ulrich Wiesner, Timothy D Wilkinson, Jeremy J Baumberg, Ullrich Steiner, Bodo D Wilts, Ilja Gunkel
Block copolymer (BCP) self-assembly is a promising route to manufacture functional nanomaterials for applications from nanolithography to optical metamaterials. Self-assembled cubic morphologies cannot, however, be conveniently optically characterized in the lab due to their structural isotropy. Here, the aligned crystallization behavior of a semicrystalline-amorphous polyisoprene-b-polystyrene-b-poly(ethylene oxide) (ISO) triblock terpolymer was utilized to visualize the grain structure of the cubic microphase-separated morphology...
August 22, 2017: Macromolecules
M ElKabbash, E Ilker, T Letsou, N Hoffman, A Yaney, M Hinczewski, G Strangi
Perfect light absorption in the visible and near-infrared (NIR) was demonstrated using metamaterials, plasmonic nanostructures, and thin films. Thin film absorbers offer a simple and low-cost design as they can be produced on large areas and without lithography. Light is strongly absorbed in thin film metal-dielectric-metal (MDM) cavities at their resonance frequencies. However, a major drawback of MDM absorbers is their strong resonance iridescence, i.e., angle dependence. Here, we solve the iridescence problem by achieving angle-insensitive narrowband perfect and near-perfect light absorption...
September 15, 2017: Optics Letters
Bui Son Tung, Bui Xuan Khuyen, Young Ju Kim, Vu Dinh Lam, Ki Won Kim, YoungPak Lee
We numerically and experimentally investigated a dual-band metamaterial perfect absorber (MPA), utilizing the near-field coupling of double split-ring resonators (DSRRs). Owing to the near-field coupling between resonators, two arms in each DSRR resonate in different phases, leading to a dual-band perfect absorption. The proposed MPA also exhibits polarization-insensitive behavior and maintains the high absorption above 90% up to a wide range of incident angle more than 45°. Finally, to further consolidate our approach, a multi-band absorption is also studied by exploiting the near-field coupling among a larger number of DSRRs...
September 14, 2017: Scientific Reports
Zhen-Guo Liu, Wei-Bing Lu, Wu Yang
In this paper, a novel explanation on high directive emission of Fabry-Perot resonator antenna with subwavelength metasurface is proposed. Based on image theory and effective constitutive parameter retrieval, the whole Fabry-Perot resonant cavity structure composed of a single-layer metasurface with square ring element and a PEC ground plate can be acted as an effective metamaterial media with very low refractive index (near zero index). According to Snell's theory, this property can be used to enhance the directive emission...
September 13, 2017: Scientific Reports
Rita Schmidt, Andrew Webb
Magnetic resonance imaging and spectroscopy (MRI and MRS) are both widely used techniques in medical diagnostics and research. One of the major thrusts in recent years has been the introduction of ultra-high field magnets in order to boost the sensitivity. Several MRI studies have examined further potential improvements in sensitivity using metamaterials, focusing on single frequency applications. However, metamaterials have yet to reach a level which is practical for routine MRI use. In this work, we explore a new metamaterial implementation for MRI, a dual-nuclei resonant structure, which can be used for both proton and heteronuclear magnetic resonance...
September 13, 2017: ACS Applied Materials & Interfaces
Fuyong Yue, Xiaofei Zang, Dandan Wen, Zile Li, Chunmei Zhang, Huigang Liu, Brian D Gerardot, Wei Wang, Guoxing Zheng, Xianzhong Chen
An optical illusion, such as "Rubin's vase", is caused by the information gathered by the eye, which is processed in the brain to give a perception that does not tally with a physical measurement of the stimulus source. Metasurfaces are metamaterials of reduced dimensionality which have opened up new avenues for flat optics. The recent advancement in spin-controlled metasurface holograms has attracted considerate attention, providing a new method to realize optical illusions. We propose and experimentally demonstrate a metasurface device to generate an optical illusion...
September 12, 2017: Scientific Reports
JingYa Xie, Xi Zhu, XiaoFei Zang, QingQing Cheng, YangYang Ye, YiMing Zhu
A high extinction ratio (ER) electromagnetically induced transparency (EIT) analogue based on single-layer metamaterial is designed and experimentally demonstrated in this paper. This design involves four mirror-like symmetrically coupled split ring resonators (SRRs) that exhibit a bright-dark-dark-bright mode configuration. The EIT-like effect is realized by coupling between the bright resonators and dark resonators. The high ER feature is achieved from the suppression of radiative losses, due to opposite directions of electric and magnetic dipoles of two dark modes in the unit cell...
September 12, 2017: Scientific Reports
Wendao Xu, Lijuan Xie, Yibin Ying
Terahertz (THz) technology has attracted great worldwide interest and novel high-intensity THz sources and plasmonics are two of the most active fields of recent research. Being situated between infrared light and microwave radiation, the absorption of THz rays in molecular and biomolecular systems is dominated by the excitation of intramolecular and intermolecular vibrations. This indicates that THz technology is an effective tool for sensing applications. However, the low sensitivity of free-space THz detection limits the sensing applications, which gives a great opportunity to metamaterials...
September 12, 2017: Nanoscale
Osamu Takayama, Andrey Bogdanov, Andrei V Lavrinenko
A surface wave (SW) in optics is a light wave, which is supported at an interface of two dissimilar media and propagates along the interface with its field amplitude exponentially decaying away from the boundary. The research on surface waves has been flourishing in last few decades thanks to their unique properties of surface sensitivity and field localization. These features have resulted in applications in nano-guiding, sensing, light-trapping and imaging based on the near-field techniques, contributing to the establishment of the nanophotonics as a field of research...
September 12, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Benjamin T Diroll, Katelyn S Schramke, Peijun Guo, Uwe R Kortshagen, Richard D Schaller
Dynamic optical control of infrared (IR) transparency and refractive index is achieved using boron-doped silicon nanocrystals excited with mid-IR optical pulses. Unlike previous silicon-based optical switches, large changes in transmittance are achieved without a fabricated structure by exploiting strong light coupling of the localized surface plasmon resonance (LSPR) produced from free holes of p-type silicon nanocrystals. The choice of optical excitation wavelength allows for selectivity between hole heating and carrier generation through intraband or interband photoexcitation, respectively...
September 18, 2017: Nano Letters
Yunuen Montelongo, Debabrata Sikdar, Ye Ma, Alastair J S McIntosh, Leonora Velleman, Anthony R Kucernak, Joshua B Edel, Alexei A Kornyshev
Recently, there has been a drive to design and develop fully tunable metamaterials for applications ranging from new classes of sensors to superlenses among others. Although advances have been made, tuning and modulating the optical properties in real time remains a challenge. We report on the first realization of a reversible electrotunable liquid mirror based on voltage-controlled self-assembly/disassembly of 16 nm plasmonic nanoparticles at the interface between two immiscible electrolyte solutions. We show that optical properties such as reflectivity and spectral position of the absorption band can be varied in situ within ±0...
September 11, 2017: Nature Materials
Kun Song, Zhaoxian Su, Min Wang, Sinhara Silva, Khagendra Bhattarai, Changlin Ding, Yahong Liu, Chunrong Luo, Xiaopeng Zhao, Jiangfeng Zhou
Because of the strong inherent resonances, the giant optical activity obtained via chiral metamaterials generally suffers from high dispersion, which has been a big stumbling block to broadband applications. In this paper, we propose a type of planar chiral metamaterial consisting of interconnected metal helix slat structures with four-fold symmetry, which exhibits nonresonant Drude-like response and can therefore avoid the highly dispersive optical activity resulting from resonances. It shows that the well-designed chiral metamaterial can achieve nondispersive and pure optical activity with high transmittance in a broadband frequency range...
September 6, 2017: Scientific Reports
Ruiping Bai, Cong Zhang, Xintong Gu, Xing Ri Jin, Ying Qiao Zhang, YoungPak Lee
An effective scheme on switching the exceptional point(EP) where unidirectional reflectionlessness occurs is firstly proposed in non-ideal PT metamaterial via the polarization of incident light. The unidirectional reflectionlessness could be effectively controlled only by adjusting the phase coupling of the two resonators which are consisted of two identical but vertically placed crosses and are excited by incident light as an effective gain. Besides, the unidirectional perfect absorber occurs in the vicinity of EP...
September 6, 2017: Scientific Reports
Niloufar Raeis-Hosseini, Junsuk Rho
Integration of phase-change materials (PCMs) into electrical/optical circuits has initiated extensive innovation for applications of metamaterials (MMs) including rewritable optical data storage, metasurfaces, and optoelectronic devices. PCMs have been studied deeply due to their reversible phase transition, high endurance, switching speed, and data retention. Germanium-antimony-tellurium (GST) is a PCM that has amorphous and crystalline phases with distinct properties, is bistable and nonvolatile, and undergoes a reliable and reproducible phase transition in response to an optical or electrical stimulus; GST may therefore have applications in tunable photonic devices and optoelectronic circuits...
September 6, 2017: Materials
C Chong, Mason A Porter, P G Kevrekidis, C Daraio
The study of granular crystals, which are nonlinear metamaterials that consist of closely packed arrays of particles that interact elastically, is a vibrant area of research that combines ideas from disciplines such as materials science, nonlinear dynamics, and condensed-matter physics. Granular crystals exploit geometrical nonlinearities in their constitutive microstructure to produce properties (such as tunability and energy localization) that are not conventional to engineering materials and linear devices...
September 6, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Shumin Zhao, Hao Chi Zhang, Jiahao Zhao, Wen Xuan Tang
In this paper, we propose a scheme to construct a new type of ultra-compact rejection filter by loading split-ring resonators (SRRs) on the transmission line of spoof surface plasmon polaritons (SPPs). From the dispersion analysis of the spoof SPP transmission line with and without the SRR loading, we clearly reveal the mechanism of the rejection characteristic for this compact filter. Meanwhile, we fabricate two spoof SPPs waveguides loaded with different amounts of metamaterials particles, and experimentally test them using an Agilent Vector Network Analyzer (VNA) and a homemade near-field scanning system...
September 5, 2017: Scientific Reports
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