scholarly journals High focusing efficiency in subdiffraction focusing metalens

Nanophotonics ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 1279-1289 ◽  
Author(s):  
Ze-Peng Zhuang ◽  
Rui Chen ◽  
Zhi-Bin Fan ◽  
Xiao-Ning Pang ◽  
Jian-Wen Dong
Keyword(s):  
High Efficiency ◽  
Numerical Aperture ◽  
Polarized Light ◽  
Optical Loss ◽  
Super Resolution ◽  
Transmission Efficiency ◽  
Optical Elements ◽  
Full Wave ◽  
Phase Profile ◽  
Subdiffraction Focusing

AbstractVector beams with phase modulation in a high numerical aperture system are able to break through the diffraction limit. However, the implementation of such a device requires a combination of several discrete bulky optical elements, increasing its complexity and possibility of the optical loss. Dielectric metalens, an ultrathin and planar nanostructure, has a potential to replace bulky optical elements, but its optimization with full-wave simulations is time-consuming. In this paper, an accurate and efficient theoretical model of planar metalens is developed. Based on this model, a twofold optimization scheme is proposed for optimizing the phase profile of metalenses so as to achieve subdiffraction focusing with high focusing efficiency. Then, a metalens that enables to simultaneously generate radially polarized beam (RPB) and modulate its phase under the incidence of x-polarized light with the wavelength of 532 nm is designed. Full-wave simulations show that the designed metalens of NA = 0.95 can achieve subdiffraction focusing (FWHM = 0.429λ) with high transmission efficiency (77.6%) and focusing efficiency (17.2%). Additionally, superoscillation phenomenon is found, leading to a compromise between the subdiffraction spot and high efficiency. The proposed method may provide an accurate and efficient way to achieve sub-wavelength imaging with the expected performances, which shows a potential application in super-resolution imaging.

scholarly journals Broadband high-efficiency dielectric metasurfaces for the visible spectrum

2016 ◽  
Vol 113 (38) ◽  
pp. 10473-10478 ◽  
Author(s):  
Robert C. Devlin ◽  
Mohammadreza Khorasaninejad ◽  
Wei Ting Chen ◽  
Jaewon Oh ◽  
Federico Capasso
Keyword(s):  
High Performance ◽  
High Efficiency ◽  
Numerical Aperture ◽  
Optical Loss ◽  
Visible Spectrum ◽  
Optical Element ◽  
Atomic Layer ◽  
Optical Elements ◽  
Layer Deposition ◽  
Visible Wavelengths

Metasurfaces are planar optical elements that hold promise for overcoming the limitations of refractive and conventional diffractive optics. Original dielectric metasurfaces are limited to transparency windows at infrared wavelengths because of significant optical absorption and loss at visible wavelengths. Thus, it is critical that new materials and nanofabrication techniques be developed to extend dielectric metasurfaces across the visible spectrum and to enable applications such as high numerical aperture lenses, color holograms, and wearable optics. Here, we demonstrate high performance dielectric metasurfaces in the form of holograms for red, green, and blue wavelengths with record absolute efficiency (>78%). We use atomic layer deposition of amorphous titanium dioxide with surface roughness less than 1 nm and negligible optical loss. We use a process for fabricating dielectric metasurfaces that allows us to produce anisotropic, subwavelength-spaced dielectric nanostructures with shape birefringence. This process is capable of realizing any high-efficiency metasurface optical element, e.g., metalenses and axicons.

scholarly journals Pre-post synaptic alignment through neuroligin tunes synaptic transmission efficiency

2017 ◽  
Author(s):  
Kalina T. Haas ◽  
Benjamin Compans ◽  
Mathieu Letellier ◽  
Thomas M Bartol ◽  
Dolors Grillo-Bosch ◽  
...  
Keyword(s):  
Synaptic Transmission ◽  
Computer Modeling ◽  
Single Molecule ◽  
High Efficiency ◽  
Super Resolution ◽  
Transmission Efficiency ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Adhesion Protein ◽  
Synaptic Release

SummaryThe nanoscale organization of neurotransmitter receptors relative to pre-synaptic release sites is a fundamental determinant of both the amplitude and reliability of synaptic transmission. How modifications in the alignment between pre- and post-synaptic machineries affect synaptic current properties has only been addressed with computer modeling, and therefore remains hypothetical. Using dual-color single molecule based super-resolution microscopy, we found a strong spatial correlation between AMPA receptor (AMPAR) nanodomains and the post-synaptic adhesion protein neuroligin-1 (NLG1). Expression of a C-terminal truncated form of NLG1 disrupted this correlation without affecting the intrinsic organization of AMPAR nanodomains. Moreover, this NLG1 dominant-negative mutant significantly shifted the pre-synaptic release machinery from AMPAR synaptic clusters. Electrophysiology and computer modeling show that this physical shift is sufficient to induce a significant decrease in synaptic transmission. Thus, our results suggest the necessity for synapses to release glutamate in front of AMPAR nanodomains, to maintain a high efficiency of synaptic responses.

On resolving fine periodic microstructures in the optical microscope

1989 ◽  
Vol 47 ◽  
pp. 364-365
Author(s):  
W.S. Putnam ◽  
C. Viney
Keyword(s):  
Liquid Crystalline ◽  
Numerical Aperture ◽  
Polarized Light ◽  
Normal Incidence ◽  
Optical Microscope ◽  
Angle Of Incidence ◽  
Resolution Limit ◽  
Crystalline Materials ◽  
Periodic Microstructures ◽  
Liquid Crystalline Materials

Many sheared liquid crystalline materials (fibers, films and moldings) exhibit a fine banded microstructure when observed in the polarized light microscope. In some cases, for example Kevlar® fiber, the periodicity is close to the resolution limit of even the highest numerical aperture objectives. The periodic microstructure reflects a non-uniform alignment of the constituent molecules, and consequently is an indication that the mechanical properties will be less than optimal. Thus it is necessary to obtain quality micrographs for characterization, which in turn requires that fine detail should contribute significantly to image formation.It is textbook knowledge that the resolution achievable with a given microscope objective (numerical aperture NA) and a given wavelength of light (λ) increases as the angle of incidence of light at the specimen surface is increased. Stated in terms of the Abbe resolution criterion, resolution improves from λ/NA to λ/2NA with increasing departure from normal incidence.

scholarly journals 3D super-resolved imaging in live cells using sub-diffractive plasmonic localization of hybrid nanopillar arrays

Nanophotonics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 2847-2859
Author(s):  
Soojung Kim ◽  
Hyerin Song ◽  
Heesang Ahn ◽  
Seung Won Jun ◽  
Seungchul Kim ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Imaging Techniques ◽  
Optical Loss ◽  
Super Resolution ◽  
Living Cells ◽  
Live Cells ◽  
Complex Biological System ◽  
Observation Volume ◽  
Resolution Imaging ◽  
Nanopillar Arrays

AbstractAnalysing dynamics of a single biomolecule using high-resolution imaging techniques has been had significant attentions to understand complex biological system. Among the many approaches, vertical nanopillar arrays in contact with the inside of cells have been reported as a one of useful imaging applications since an observation volume can be confined down to few-tens nanometre theoretically. However, the nanopillars experimentally are not able to obtain super-resolution imaging because their evanescent waves generate a high optical loss and a low signal-to-noise ratio. Also, conventional nanopillars have a limitation to yield 3D information because they do not concern field localization in z-axis. Here, we developed novel hybrid nanopillar arrays (HNPs) that consist of SiO2 nanopillars terminated with gold nanodisks, allowing extreme light localization. The electromagnetic field profiles of HNPs are obtained through simulations and imaging resolution of cell membrane and biomolecules in living cells are tested using one-photon and 3D multiphoton fluorescence microscopy, respectively. Consequently, HNPs present approximately 25 times enhanced intensity compared to controls and obtained an axial and lateral resolution of 110 and 210 nm of the intensities of fluorophores conjugated with biomolecules transported in living cells. These structures can be a great platform to analyse complex intracellular environment.

scholarly journals High-Efficiency, Dual-Band Beam Splitter Based on an All-Dielectric Quasi-Continuous Metasurface

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3184
Author(s):  
Jing Li ◽  
Yonggang He ◽  
Han Ye ◽  
Tiesheng Wu ◽  
Yumin Liu ◽  
...  
Keyword(s):  
Wavelength Range ◽  
Conversion Efficiency ◽  
Antenna Arrays ◽  
Beam Splitter ◽  
High Efficiency ◽  
Visible Region ◽  
Polarized Light ◽  
Dual Band ◽  
Phase Gradient ◽  
Total Transmission

Metasurface-based beam splitters attracted huge interest for their superior properties compared with conventional ones made of bulk materials. The previously reported designs adopted discrete metasurfaces with the limitation of a discontinuous phase profile. In this paper, we propose a dual-band beam splitter, based on an anisotropic quasi-continuous metasurface, by exploring the optical responses under x-polarized (with an electric field parallel to the direction of the phase gradient) and y-polarized incidences. The adopted metasurface consists of two identical trapezoidal silicon antenna arrays with opposite spatial variations that lead to opposite phase gradients. The operational window of the proposed beam splitter falls in the infrared and visible region, respectively, for x- and y-polarized light, resulting from the different mechanisms. When x-polarized light is incident, the conversion efficiency and total transmission of the beam splitter remains higher than 90% and 0.74 within the wavelength range from 969 nm to 1054 nm, respectively. In this condition, each array can act as a beam splitter of unequal power. For y-polarized incidence, the maximum conversion efficiency and transmission reach approximately 100% and 0.85, while the values remain higher than 90% and 0.65 in the wavelength range from 687 nm to 710 nm, respectively. In this case, each array can be viewed as an effective beam deflector. We anticipate that it can play a key role in future integrated optical devices.

scholarly journals Ultrawide-angle and high-efficiency metalens in hexagonal arrangement

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chun-Yuan Fan ◽  
Chia-Ping Lin ◽  
Guo-Dung J. Su
Keyword(s):  
High Efficiency ◽  
Numerical Aperture ◽  
Vital Role ◽  
Optical Systems ◽  
Wide Field ◽  
Wide Angle ◽  
Camera Systems ◽  
Single Lens ◽  
Hexagonal Arrangement ◽  
Virtual And Augmented Reality

Abstract Wide-angle optical systems play a vital role in imaging applications and have been researched for many years. In traditional lenses, attaining a wide field of view (FOV) by using a single optical component is difficult because these lenses have crucial aberrations. In this study, we developed a wide-angle metalens with a numerical aperture of 0.25 that provided a diffraction-limited FOV of over 170° for a wavelength of 532 nm without the need for image stitching or multiple lenses. The designed wide-angle metalens is free of aberration and polarization, and its full width of half maximum is close to the diffraction limit at all angles. Moreover, the metalens which is designed through a hexagonal arrangement exhibits higher focusing efficiency at all angles than most-seen square arrangement. The focusing efficiencies are as high as 82% at a normal incident and 45% at an incident of 85°. Compared with traditional optical components, the proposed metalens exhibits higher FOV and provides a more satisfactory image quality because of aberration correction. Because of the advantages of the proposed metalens, which are difficult to achieve for a traditional single lens, it has the potential to be applied in camera systems and virtual and augmented reality.

scholarly journals Optimal design of high efficiency double helical gear based on dynamics model

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Fengxia Lu ◽  
Xuechen Cao ◽  
Weiping Liu
Keyword(s):  
Dynamic Model ◽  
High Efficiency ◽  
Bending Strength ◽  
Sliding Friction ◽  
Elastohydrodynamic Lubrication ◽  
Optimization Method ◽  
Transmission Efficiency ◽  
Helical Gear ◽  
Transmission System ◽  
Vibration Displacement

AbstractA 16-degree-of-freedom dynamic model for the load contact analysis of a double helical gear considering sliding friction is established. The dynamic equation is solved by the Runge–Kutta method to obtain the vibration displacement. The method combines the friction coefficient model based on the elastohydrodynamic lubrication theory with the dynamic model, which provides a theoretical basis for the calculation of the power loss of the transmission system. Moreover, the sensitivity analysis of the parameters that affect the transmission efficiency is carried out, and an optimization method of meshing efficiency is proposed without reducing the bending strength of the gears. This method can directly guide the design of the double helical gear transmission system.

High-efficiency generation of circularly polarized light via symmetry-induced anomalous reflection

2015 ◽  
Vol 91 (12) ◽  
Author(s):  
Shang-Chi Jiang ◽  
Xiang Xiong ◽  
Yuan-Sheng Hu ◽  
Sheng-Wei Jiang ◽  
Yu-Hui Hu ◽  
...  
Keyword(s):  
High Efficiency ◽  
Polarized Light ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Anomalous Reflection

scholarly journals Improved Experimental Procedures for Achieving Efficient Germ Line Transmission of Nonobese Diabetic (NOD)-Derived Embryonic Stem Cells

2004 ◽  
Vol 5 (3) ◽  
pp. 219-226 ◽  
Author(s):  
Satoko Arai ◽  
Christina Minjares ◽  
Seiho Nagafuchi ◽  
Toru Miyazaki
Keyword(s):  
High Efficiency ◽  
Germ Line ◽  
Gene Knockout ◽  
Es Cells ◽  
Embryonic Stem ◽  
Nod Mice ◽  
Insulin Dependent Diabetes Mellitus ◽  
Transmission Efficiency ◽  
Dependent Diabetes Mellitus ◽  
Specific Gene

The manipulation of a specific gene in NOD mice, the best animal model for insulin-dependent diabetes mellitus (IDDM), must allow for the precise characterization of the functional involvement of its encoded molecule in the pathogenesis of the disease. Although this has been attempted by the cross-breeding of NOD mice with many gene knockout mice originally created on the 129 or C57BL/6 strain background, the interpretation of the resulting phenotype(s) has often been confusing due to the possibility of a known or unknown disease susceptibility locus (e.g.,Iddlocus) cosegregating with the targeted gene from the diabetes-resistant strain. Therefore, it is important to generate mutant mice on a pure NOD background by using NOD-derived embryonic stem (ES) cells. By using the NOD ES cell line established by Nagafuchi and colleagues in 1999 (FEBSLett., 455, 101–104), the authors reexamined various conditions in the context of cell culture, DNA transfection, and blastocyst injection, and achieved a markedly improved transmission efficiency of these NOD ES cells into the mouse germ line. These modifications will enable gene targeting on a “pure” NOD background with high efficiency, and contribute to clarifying the physiological roles of a variety of genes in the disease course of IDDM.

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