The efficient manipulation of light-matter interactions in subwavelength all-dielectric nanostructures offers a unique opportunity for the design of novel low-loss visible- and telecom-range nanoantennas for light routing applications. Several studies have achieved longitudinal and transverse light scattering with a proper amplitude and phase balance among the multipole moments excited in dielectric nanoantennas. However, they only involve the interaction between electric dipole, magnetic dipole, and up to the electric quadrupole. Here, we extend and demonstrate a unidirectional transverse light scattering in a V-shaped silicon nanoantenna that involves the balance up to the magnetic quadrupole moment. Based on the long-wavelength approximation and exact multipole decomposition analysis, we find the interference conditions needed for near-unity unidirectional transverse light scattering along with near-zero scattering in the opposite direction. These interference conditions involve relative amplitude and phases of the electromagnetic dipoles and quadrupoles supported by the silicon nanoantenna. The conditions can be applied for the development of either polarization- or wavelength- dependent light routing on a V-shaped silicon and plasmonic nanoantennas.
Perfect magnetic mirrors are important optical devices for the development of novel optical detectors, solar cells, and imaging devices. They have the property of only reversing the magnetic field of a light wave upon reflection, for instance, in functional optical metasurfaces. To design an optical magnetic mirror, high-refractive-index dielectric nanostructures that support strong magnetic dipole (MD) response in the optical wavelength range are used. However, the spectral overlap between the MD and electric dipole in dielectric resonators degrades the magnetic mirror reflection. Here, we propose and demonstrate a perfect optical magnetic mirror metasurface that totally reflects an incident wave without electric field phase change. In this perfect magnetic mirror, the electric dipole radiation is completely suppressed by the radiation of the anapole mode in the spectral range where the destructive interference between the electric dipole and toroidal dipole occurs. By fine-tuning the size parameters of the dielectric resonators, we show near-perfect MD scattering as a result of the spectral overlap between MD resonance and anapole mode. The optical magnetic mirror can be tuned from the visible to near-infrared range by scaling the sizes of the resonators. The MD scattering resonators promote the perfect magnetic mirror, a promising platform for designing photodetectors, biological sensors, and reflected waveplates.
Microscale (<5μm) gas breakdown is usually dominated by field emission, which is influenced largely by electrode surface morphology. At present, there is a large number of studies on the breakdown and discharge of different metal electrode geometry and electrode spacing as well as MEMS device structures, but few studies on the breakdown of MEMS electrodes affected by notching, which will greatly change the electrode surface morphology but is difficult to completely avoid in DRIE process based on SOI wafer. In response to this situation, this paper conducted breakdown tests and field emission tests on MEMS samples with and without notching. It was found that samples with notching could withstand more breakdowns of about 6-13 times before the formation of internal resistance, increased by 200%-300% compared with samples without notching, and have a lower breakdown voltage of about 210V, 16% lower than that of samples without notching. In addition, it was also found that for the samples with notching, the field enhancement factor gradually decreases with the increase of the number of breakdown events. When the field enhancement factor decreases to about 100, the subsequent breakdown is highly likely to cause the sample to form electrical connection, thus completely damaging the sample. Above conclusions have certain reference value for designing the actuation voltage of MEMS devices based on SOI wafers.
Point-pair registration in a real scene remains a challenging task, due to the complexity of solving three transformations (scale, rotation, and displacement) simultaneously, and the influence of noise and outliers. Aimed at this problem, a registration algorithm based on histogram and vector operations is proposed in this paper. This approach converts point-based operations into vector-based operations, thereby decomposing the registration process into three independent steps solving for scale transformation factors, rotation matrices, and displacement vectors, which reduces the complexity of the solution and avoids the effects of scaling in the other two processes. The influence of outliers on the global transformation matrix is simultaneously eliminated using a histogram-based approach. Algorithm performance was evaluated through a comparison with the most commonly used SVD method in a series of validation experiments, with results showing that our methodology was superior to SVD in the cases with scaling transformation or outliers.
This paper proposes a novel method for enhancing the dynamic range of structured-light cameras to solve the problem of highlight that occurs when 3D modeling highly reflective objects using the structured-light method. Our method uses the differences in quantum efficiency between R, G, and B pixels in the color image sensor of a monochromatic laser to obtain structured-light images of an object under test with different luminance values. Our approach sacrifices the resolution of the image sensor to increase the dynamic range of the vision system. Additionally, to enhance our system, we leverage the backgrounds of structured-light stripe pattern images to restore the color information of measured objects, whereas the background is often removed as noise in other 3D reconstruction systems. This reduces the number of cameras required for 3D reconstruction and the matching error between point clouds and color data. We modeled both highly reflective and non-highly reflective objects and achieved satisfactory results.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.