scholarly journals High-performance asymmetric optical transmission based on coupled complementary subwavelength gratings

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Shuang Li ◽  
Li-rong Huang ◽  
Yong-hong Ling ◽  
Wen-bing Liu ◽  
Chun-fa Ba ◽  
...  
Keyword(s):  
High Performance ◽  
Optical Transmission ◽  
Coupling Effect ◽  
Dipole Moments ◽  
Near Field ◽  
Optical Computing ◽  
Asymmetric Transmission ◽  
Subwavelength Gratings ◽  
Application Fields ◽  
Dielectric Environment

AbstractAsymmetric transmission (AT) devices are fundamental elements for optical computing and information processing. We here propose an AT device consisting of a pair of coupled complementary subwavelength gratings. Different from previous works, asymmetric dielectric environment is employed for unidirectional excitation of surface plasmon polaritons (SPPs) and thus asymmetric optical transmission, and near-field coupling effect inherent in the coupled complementary structure is exploited to enhance forward transmission and AT behavior, and determine operation bandwidth as well. The influence of asymmetric dielectric environment, effect of vertical and lateral couplings, interactions of electric- and magnetic-dipole moments and the realization of Kerker conditions, are investigated in depth to unearth the AT mechanism and performance. High-performance AT with large forward transmittance of 0.96 and broad bandwidth of 174 nm is achieved at wavelength 1250 nm. Our work helps people to gain a better understanding of near-filed coupling effect in coupled complementary structures, expand their application fields, and it also offers an alternate way to high-performance AT devices.

scholarly journals High-Performance Asymmetric Optical Transmission Based on a Dielectric–Metal Metasurface

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2410
Author(s):  
Wenbing Liu ◽  
Lirong Huang ◽  
Jifei Ding ◽  
Chenkai Xie ◽  
Yi Luo ◽  
...  
Keyword(s):  
High Performance ◽  
Optical Transmission ◽  
Near Infrared ◽  
Contrast Ratio ◽  
Polarized Light ◽  
Infrared Region ◽  
Optical Systems ◽  
Asymmetric Transmission ◽  
Linearly Polarized ◽  
Transmittance Peak

Asymmetric optical transmission plays a key role in many optical systems. In this work, we propose and numerically demonstrate a dielectric–metal metasurface that can achieve high-performance asymmetric transmission for linearly polarized light in the near-infrared region. Most notably, it supports a forward transmittance peak (with a transmittance of 0.70) and a backward transmittance dip (with a transmittance of 0.07) at the same wavelength of 922 nm, which significantly enhances operation bandwidth and the contrast ratio between forward and backward transmittances. Mechanism analyses reveal that the forward transmittance peak is caused by the unidirectional excitation of surface plasmon polaritons and the first Kerker condition, whereas the backward transmittance dip is due to reflection from the metal film and a strong toroidal dipole response. Our work provides an alternative and simple way to obtain high-performance asymmetric transmission devices.

scholarly journals Asymmetric Transmission in a Mie-Based Dielectric Metamaterial with Fano Resonance

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1003 ◽  
Author(s):  
Xiaobo Wang ◽  
Haohua Li ◽  
Ji Zhou
Keyword(s):  
High Performance ◽  
Near Field ◽  
Destructive Interference ◽  
Asymmetric Transmission ◽  
Microwave Frequencies ◽  
Chiral Metamaterials ◽  
Field Coupling ◽  
Polarized Waves ◽  
Linearly Polarized ◽  
Polarization Rotators

Chiral metamaterials with asymmetric transmission can be applied as polarization-controlled devices. Here, a Mie-based dielectric metamaterial with a spacer exhibiting asymmetric transmission of linearly polarized waves at microwave frequencies was designed and demonstrated numerically. The unidirectional characteristic is attributed to the chirality of the metamolecule and the mutual excitation of the Mie resonances. Field distributions are simulated to investigate the underlying physical mechanism. Fano-type resonances emerge near the Mie resonances of the constituents and come from the destructive interference inside the structure. The near-field coupling further contributes to the asymmetric transmission. The influences of the lattice constant and the spacer thickness on the asymmetric characteristics were also analyzed by parameter sweeps. The proposed Mie-based metamaterial is of a simple structure, and it has the potential for applications in dielectric metadevices, such as high-performance polarization rotators.

scholarly journals A Unified Model to Explain the Large Chiroptical Effects in Polymer Systems Through Natural Optical Activity

2020 ◽  
Author(s):  
Jess Wade ◽  
James Hilfiker ◽  
Jochen Brandt ◽  
Letizia Liirò-Peluso ◽  
Li Wan ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Activity ◽  
High Performance ◽  
Dipole Moments ◽  
Magnetic Transition ◽  
Polymer Thin Films ◽  
Device Fabrication ◽  
Local Order ◽  
Transition Dipole ◽  
Technological Advances

<div><div><div><p>Polymer thin films that emit and absorb circularly polarised light have been demonstrated with the promise of achieving important technological advances; from efficient, high-performance displays, to 3D imaging and all-organic spintronic devices. However, the origin of the large chiroptical effects in such films has, until now, remained elusive. We investigate the emergence of such phenomena in achiral polymers blended with a chiral small-molecule additive (1-aza[6]helicene) and intrinsically chiral-sidechain polymers using a combination of spectroscopic methods and structural probes. We show that – under conditions relevant for device fabrication – the large chiroptical effects are caused by coupling of electric and magnetic transition dipole moments (natural optical activity), not structural chirality as previously assumed, and may occur because of local order in a cylinder blue phase-type organisation. This disruptive mechanistic insight into chiral polymer thin films will offer new approaches towards chiroptical materials development after almost three decades of research in this area.</p></div></div></div>

scholarly journals Passive control of structures for seismic loads

2000 ◽  
Vol 33 (3) ◽  
pp. 209-221 ◽  
Author(s):  
Ian G. Buckle
Keyword(s):  
High Performance ◽  
Passive Control ◽  
Base Isolation ◽  
Mechanical Energy ◽  
Near Field ◽  
The United States ◽  
Industrial Plant ◽  
Passive Systems ◽  
Limit States ◽  
Existing Structures

The control of structures to improve their performance during earthquakes was first proposed more than a century ago. But it has only been in the last 25 years that structures have been successfully designed and built using earthquake protective systems. Today these systems range from simple passive devices to fully active systems. This paper focuses on passive control and reviews recent developments in the state-of-the-art. Passive systems include tuned mass dampers, seismic (base) isolation systems, mechanical energy dissipators, and the like. Major developments in the theory, hardware, design, specification, and installation of these systems have permitted significant applications to buildings, bridges, and industrial plant. Applications are now found in almost all of the seismically active countries of the world, but principally in Italy, Japan, New Zealand and the United States. Noteworthy advantages have been demonstrated when retrofitting existing structures, and designing high-performance structures such as hospitals, emergency response facilities, defense installations, and critical bridges. Field experience in recent earthquakes has confirmed these expectations. There are however limitations to the use of passive systems and these deserve further study and research. They include the uncertainty of response in the near field of an active fault, the non- optimal behavior of passive systems for both small and large earthquakes, and a lack of certainty about the ultimate limit states in unexpectedly large events. As a consequence, in some jurisdictions, code provisions for passive systems are more onerous than for conventional construction, which is a strong disincentive to their use. The limited availability of design guidance in text books, code commentaries, and other design aids are further impediments to the wider use of these systems.

scholarly journals Coupling Parameters for Modeling the Near-Field Heat Transfer Between Molecules

2021 ◽  
Vol 9 ◽  
Author(s):  
Karthik Sasihithlu
Keyword(s):  
Heat Transfer ◽  
Energy Transfer ◽  
Dipole Moments ◽  
Near Field ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Orientation Factor ◽  
Dipole Interactions ◽  
Coupling Parameters ◽  
Drude Oscillators

The behavior of near-field heat transfer between molecules at gaps which are small compared to wavelength of light is greatly influenced by non-radiative dipole-dipole interactions between the molecules. Here we derive the coupling parameters and estimate the near-field heat transfer between two molecules using coupled Drude oscillators. The predictions from this model are verified with results from standard fluctuational electrodynamics principles. The effect of orientation factor of the dipole moments in the molecules traditionally taken into consideration for analysis of resonance energy transfer between molecules but hitherto overlooked for near-field heat transfer is also discussed.

scholarly journals High-Performance and Small-Form Factor Near-Field Inductive Coupling for 3-D NoC

2018 ◽  
Vol 26 (12) ◽  
pp. 2921-2934 ◽  
Author(s):  
Srinivasan Gopal ◽  
Sourav Das ◽  
Pawan Agarwal ◽  
Sheikh Nijam Ali ◽  
Deukhyoun Heo ◽  
...  
Keyword(s):  
Form Factor ◽  
High Performance ◽  
Near Field ◽  
Inductive Coupling ◽  
Small Form ◽  
Small Form Factor

Extraordinary optical transmission from a thin microcavity by macroscopic quantum effect

2021 ◽  
Author(s):  
Lin Zhang ◽  
Jiu Hui Wu
Keyword(s):  
Edge Effect ◽  
Optical Transmission ◽  
Critical Radius ◽  
Quantum Effect ◽  
Near Field ◽  
Extraordinary Optical Transmission ◽  
Wave Regime ◽  
Incident Wavelength ◽  
Macroscopic Quantum ◽  
Wave Particle Duality

Abstract The macroscopic quantum effect is revealed to elaborate the extraordinary optical transmission (EOT) from a subwavelength thin microcavity based on the uncertainty property of the transmitted electromagnetic fields after the aperture. A critical radius is found in the thin microcavity under a certain incident electromagnetic wavelength. With the aperture radius varying, the transmitted field can be divided into three regimes: I. the macroscopic quantum regime when the aperture radius is less than the critical radius, in which the field edge effect occurs and EOT phenomenon is perfectly manifested; II. The wave-particle duality regime in the vicinity of the critical radius, in which the edge effect and diffraction phenomenon exist simultaneously; III. The wave regime when the aperture radius is greater than the critical radius, in which the near-field diffraction emerges. In addition, the influences of incident wavelength and microcavity thickness on EOT are also investigated. Our research have potential applications in advanced optical devices, such as light switch and optical manipulations.

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