scholarly journals Dielectric Metalens: Properties and Three-Dimensional Imaging Applications

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4584
Author(s):  
Sun-Je Kim ◽  
Changhyun Kim ◽  
Youngjin Kim ◽  
Jinsoo Jeong ◽  
Seokho Choi ◽  
...  
Keyword(s):  
High Efficiency ◽  
Three Dimensional ◽  
Optical Systems ◽  
Functional Improvement ◽  
Depth Information ◽  
Optical Components ◽  
Three Dimensional Imaging ◽  
Wide Range ◽  
Optical Dielectric ◽  
Optical Focusing

Recently, optical dielectric metasurfaces, ultrathin optical skins with densely arranged dielectric nanoantennas, have arisen as next-generation technologies with merits for miniaturization and functional improvement of conventional optical components. In particular, dielectric metalenses capable of optical focusing and imaging have attracted enormous attention from academic and industrial communities of optics. They can offer cutting-edge lensing functions owing to arbitrary wavefront encoding, polarization tunability, high efficiency, large diffraction angle, strong dispersion, and novel ultracompact integration methods. Based on the properties, dielectric metalenses have been applied to numerous three-dimensional imaging applications including wearable augmented or virtual reality displays with depth information, and optical sensing of three-dimensional position of object and various light properties. In this paper, we introduce the properties of optical dielectric metalenses, and review the working principles and recent advances in three-dimensional imaging applications based on them. The authors envision that the dielectric metalens and metasurface technologies could make breakthroughs for a wide range of compact optical systems for three-dimensional display and sensing.

Miniature Stereo Imaging Converter With Translating Aperture

2010 ◽  
Author(s):  
Wook Choi ◽  
Vladimir Rubtsov ◽  
Chang-Jin “C. J.” Kim
Keyword(s):  
Three Dimensional ◽  
Stereo Image ◽  
Optical Systems ◽  
Depth Information ◽  
Two Dimensional ◽  
Depth Of Focus ◽  
Stereo Imaging ◽  
Wide Range ◽  
Mems Technology ◽  
Application Fields

Depth information from an image can greatly increase the work efficiency when observing or inspecting objects, because the size, distance, and relative locations can be estimated. Various stereo imaging methods are being used to find depth information in a wide range of application fields, typically by placing multiple optical systems side-by-side to create multiple shifted images. In this study, we develop a miniature stereo image generating device, which can augment an existing single optical system (i.e., a two-dimensional images capturer) with three-dimensional capability. Developed with MEMS technology, the device consists of a single translating aperture, which shifts laterally between two positions (up to 100 μm apart demonstrated) by means of electrostatic comb actuators. Attached at the objective end of conventional (i.e., nonstereo) optical systems, this stereo converter with an aperture 900 μm in diameter is shown to successfully generate slightly different viewing angles, providing stereo images. Being miniaturized, this device is suitable for microscopic or endoscopic applications, where the size of the system is limited or axial depth of focus is relatively large.

scholarly journals STRUCTURAL DEVELOPMENT AND RESEARCH OF TECHNOLOGICAL PARAMETERS OF MACHINES FOR CENTRIFUGAL -PLANETARY VIBRATION TREATMENT

2020 ◽  
pp. 41-50
Author(s):  
Leonid Yaroshenko ◽  
Igor Kupchuk ◽  
Mykhailo Zamrii
Keyword(s):  
High Efficiency ◽  
Metal Removal ◽  
Three Dimensional ◽  
High Hardness ◽  
Working Environment ◽  
Repeated Loading ◽  
Structural Development ◽  
Technological Parameters ◽  
Advantages And Disadvantages ◽  
Wide Range

The paper analyzes current state and prospects of further development of technology and equipment for mechanization and automation of finishing and cleaning of details. It is stated that the most effective for this purpose are the methods of abrasive machining, which include bulk galvanizing, vibration, centrifugal-rotary and centrifugal-planetary processing. These methods reduce the complexity and cost of processing, which in some cases reaches 20% of the total cost of manufacturing parts. Each of these methods has a different level of efficiency, certain advantages and disadvantages, the level of versatility and scope of effective application. The processes of vibration processing are quite deeply studied, for its industrial mass-produced technological equipment, but they have certain shortcomings that limit their use for further widespread implementation. Centrifugal-rotary processing is a more productive process of three-dimensional finishing and cleaning treatment, but its scope is limited by the possibility of processing parts that are not complex, usually flat. The most productive methods of finishing and cleaning of details include centrifugal-planetary volume processing which high efficiency is caused by repeated loading of particles of working load by inertial forces that creates preconditions for the solutions of a wide range of technological problems, for example, processing of details of difficult form, small weight and the sizes from materials of high hardness or viscosity that represents a serious problem for other methods of volume processing. The constructive scheme is offered in the work and the influence of the composition of the abrasive free-granular working environment on the productivity of the machine for centrifugal-planetary processing of details is investigated. The kinetics of metal removal from the surface of machined parts using different types of abrasive working environment is analyzed. The results of comparative machining of parts in a torus vibrating machine and a machine for centrifugal-planetary machining are given. It is shown that the simultaneous use of centrifugal-planetary and vibration processing methods allows to increase the intensity of the process while ensuring high quality machining of parts of relatively complex shape. The constructive scheme of the machine which allows to implement the specified combined method of processing is offered and described.

Design and manufacture of three-dimensional auxetic warp-knitted spacer fabrics based on re-entrant and rotating geometries

2021 ◽  
pp. 004051752110372
Author(s):  
Chang Yuping ◽  
Yanping Liu ◽  
Zhao Shuaiquan ◽  
Hu Hong
Keyword(s):  
High Efficiency ◽  
Three Dimensional ◽  
Fabric Structure ◽  
Spacer Fabric ◽  
Wide Range ◽  
Yarn Guide ◽  
Tensile Strains ◽  
Spacer Fabrics ◽  
Fabric Structures ◽  
Design And Manufacture

Warp knitting technology is a fabric-forming technologies that is very suitable to fabricate three-dimensional (3D) auxetic fabrics due to its high efficiency and powerful pattern designing possibilities. In this study, two typical auxetic geometries, namely the re-entrant hexagonal network and rotating square solids, were selected as the design prototypes for the design and manufacture of 3D warp-knitted spacer fabrics. While two 3D warp-knitted spacer fabric structures with representative units of different sizes designed based on the re-entrant hexagonal geometry were manufactured by using a RD7 double needle bar Raschel machine with seven yarn guide bars, two 3D jacquard warp-knitted spacer fabrics with different base fabric structures designed based on the rotating squares geometry were fabricated by using a RDPJ4/2 double needle bar jacquard machine with two ground yarn guide bars and four jacquard guide bars. The Poisson’s ratios of these 3D warp-knitted fabrics in the course direction and wale direction were evaluated respectively through constant-rate tensile tests. The results revealed that the re-entrant hexagonal fabric structure with double chain stitches has auxetic behavior across a wide range of tensile strains along the course direction, while the rotating square fabric structure with elastic chain stitches as the base is auxetic within a narrow range of tensile strains along the wale direction. The study provides an alternative method to directly produce auxetic warp-knitted spacer fabrics through a single knitting process instead of using an additional post-compression and heat-setting process.

Measurement of the polarization state of light using an integrated plasmonic polarimeter

Nanophotonics ◽  
2012 ◽  
Vol 1 (2) ◽  
pp. 125-129 ◽  
Author(s):  
Farzaneh Afshinmanesh ◽  
Justin S. White ◽  
Wenshan Cai ◽  
Mark L. Brongersma
Keyword(s):  
Polarization State ◽  
Electronic Devices ◽  
Optical Systems ◽  
Optical Components ◽  
Plasmonic Structures ◽  
Wide Range ◽  
State Of Polarization ◽  
Polarimetric Imaging ◽  
Complete State ◽  
Good Agreement

AbstractPlasmonics has started to facilitate the replacement of bulky optical components in optical systems by compact nanometallic elements that perform the same function. This allows for a natural and very dense integration with electronic devices. In this vein, we present a silicon (Si) photodetector integrated with a set of plasmonic structures that can be used as either a broadband linear-Stokes polarimeter or a narrowband full-Stokes polarimeter capable of determining the complete state of polarization of a light beam. At a probe-wavelength of 830 nm, our experimental results show contrast ratios of 25 and 1.13 for orthogonal linear and circular states of polarization, in good agreement with simulations. The resulting device is lightweight, orders of magnitude smaller than conventional polarimeters, and mechanically robust. For these reasons, there promises to be a wide range of applications including polarimetric imaging and sensing.

scholarly journals Self-organized phase-transition lithography for all-inorganic photonic textures

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Bo Zhang ◽  
Dezhi Tan ◽  
Zhuo Wang ◽  
Xiaofeng Liu ◽  
Beibei Xu ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Efficiency ◽  
Three Dimensional ◽  
Research Direction ◽  
Structural Features ◽  
Ultrafast Laser ◽  
Material System ◽  
Self Organized ◽  
Wide Range ◽  
Matter Interaction

AbstractRealizing general processing applicable to various materials by one basic tool has long been considered a distant dream. Fortunately, ultrafast laser–matter interaction has emerged as a highly universal platform with unprecedented optical phenomena and provided implementation paths for advanced manufacturing with novel functionalities. Here, we report the establishment of a three-dimensional (3D) focal-area interference field actively induced by a single ultrafast laser in transparent dielectrics. Relying on this, we demonstrate a radically new approach of self-organized phase-transition lithography (SOPTL) to achieve super-resolution construction of embedded all-inorganic photonic textures with extremely high efficiency. The generated textures exhibit a tunable photonic bandgap (PBG) in a wide range from ~1.3 to ~2 μm. More complicated interlaced textures with adjustable structural features can be fabricated within a few seconds, which is not attainable with any other conventional techniques. Evidence suggests that the SOPTL is extendable to more than one material system. This study augments light–matter interaction physics, offers a promising approach for constructing robust photonic devices, and opens up a new research direction in advanced lithography.

scholarly journals Development of synchrotron X-ray micro-tomography under extreme conditions of pressure and temperature

2017 ◽  
Vol 24 (1) ◽  
pp. 240-247 ◽  
Author(s):  
M. Álvarez-Murga ◽  
J. P. Perrillat ◽  
Y. Le Godec ◽  
F. Bergame ◽  
J. Philippe ◽  
...  
Keyword(s):  
High Pressure ◽  
Structural Changes ◽  
Three Dimensional ◽  
Crystallographic Structure ◽  
Three Dimensional Imaging ◽  
X Ray ◽  
Wide Range ◽  
Micro Tomography ◽  
Non Destructive

X-ray tomography is a non-destructive three-dimensional imaging/microanalysis technique selective to a wide range of properties such as density, chemical composition, chemical states and crystallographic structure with extremely high sensitivity and spatial resolution. Here the development of in situ high-pressure high-temperature micro-tomography using a rotating module for the Paris–Edinburgh cell combined with synchrotron radiation is described. By rotating the sample chamber by 360°, the limited angular aperture of ordinary high-pressure cells is surmounted. Such a non-destructive high-resolution probe provides three-dimensional insight on the morphological and structural evolution of crystalline as well as amorphous phases during high pressure and temperature treatment. To demonstrate the potentials of this new experimental technique the compression behavior of a basalt glass is investigated by X-ray absorption tomography, and diffraction/scattering tomography imaging of the structural changes during the polymerization of C60 molecules under pressure is performed. Small size and weight of the loading frame and rotating module means that this apparatus is portable, and can be readily installed on most synchrotron facilities to take advantage of the diversity of three-dimensional imaging techniques available at beamlines. This experimental breakthrough should open new ways for in situ imaging of materials under extreme pressure–temperature–stress conditions, impacting diverse areas in physics, chemistry, geology or materials sciences.

scholarly journals Mixing Performance of a Cost-effective Split-and-Recombine 3D Micromixer Fabricated by Xurographic Method

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 786 ◽  
Author(s):  
Ramezan Ali Taheri ◽  
Vahabodin Goodarzi ◽  
Abdollah Allahverdi
Keyword(s):  
High Efficiency ◽  
Molecular Diffusion ◽  
Low Cost ◽  
Three Dimensional ◽  
Cost Effective ◽  
Reynolds Numbers ◽  
Mixing Performance ◽  
Wide Range ◽  
Fluid Layers ◽  
Passive Micromixer

This paper presents experimental and numerical investigations of a novel passive micromixer based on the lamination of fluid layers. Lamination-based mixers benefit from increasing the contact surface between two fluid phases by enhancing molecular diffusion to achieve a faster mixing. Novel three-dimensional split and recombine (SAR) structures are proposed to generate fluid laminations. Numerical simulations were conducted to model the mixer performance. Furthermore, experiments were conducted using dyes to observe fluid laminations and evaluate the proposed mixer’s characteristics. Mixing quality was experimentally obtained by means of image-based mixing index (MI) measurement. The multi-layer device was fabricated utilizing the Xurography method, which is a simple and low-cost method to fabricate 3D microfluidic devices. Mixing indexes of 96% and 90% were obtained at Reynolds numbers of 0.1 and 1, respectively. Moreover, the device had an MI value of 67% at a Reynolds number of 10 (flow rate of 116 µL/min for each inlet). The proposed micromixer, with its novel design and fabrication method, is expected to benefit a wide range of lab-on-a-chip applications, due to its high efficiency, low cost, high throughput and ease of fabrication.

scholarly journals Si metasurface half-wave plates demonstrated on a 12-inch CMOS platform

Nanophotonics ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 149-157 ◽  
Author(s):  
Yuan Dong ◽  
Zhengji Xu ◽  
Nanxi Li ◽  
Jinchao Tong ◽  
Yuan Hsing Fu ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Optical Systems ◽  
Optical Components ◽  
Monolithically Integrated ◽  
Half Wave ◽  
Birefringent Crystals ◽  
Polarization Controlling ◽  
The Impact

AbstractHalf-wave plate (HWP) is one of the key polarization controlling devices in optical systems. The conventional HWPs based on birefringent crystals are inherently bulky and difficult to be monolithically integrated with other optical components. In this work, metasurface-based HWPs with high compactness are demonstrated on a 12-inch silicon complementary metal-oxide-semiconductor platform. Three-dimensional finite difference time domain simulation is used to design the nanostructure and investigate the impact of fabrication process variation on the device performance. In addition, the cross- and co-polarization transmittance (Tcross and Tco) of the HWPs located at different wafer locations are characterized experimentally. The peak Tcross and valley Tco values of 0.69 ± 0.053 and 0.032 ± 0.005 are realized at the wavelength around 1.7 μm, respectively. This corresponds to a polarization conversion efficiency of 95.6% ± 0.8%.

scholarly journals Mixed Halide Perovskites for High-Efficiency and Spectrally Stable Blue Light-Emitting Diodes

2020 ◽  
Author(s):  
Max Karlsson ◽  
Ziyue Yi ◽  
Sebastian Reichert ◽  
Xiyu Luo ◽  
Weihua Lin ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Three Dimensional ◽  
Blue Emission ◽  
Chloride Content ◽  
Practical Implementation ◽  
Ion Migration ◽  
Light Emitting ◽  
Wide Range ◽  
Halide Perovskites

Abstract Bright and efficient blue emission is key to further development of metal halide perovskite light-emitting diodes. Although modifying bromide/chloride composition is straightforward to achieve blue emission, practical implementation of this strategy has been challenging due to poor colour stability and severe photoluminescence quenching. Both detrimental effects become increasingly prominent in perovskites with the high chloride content that is desired to produce blue emission. Here, we solve these critical challenges in mixed halide perovskites and demonstrate spectrally stable blue perovskite light-emitting diodes (PeLEDs) over a wide range of emission wavelengths from 490 to 451 nanometres. The emission colour is directly tuned by modifying the halide composition. Particularly, our blue and deep-blue PeLEDs based on three-dimensional perovskites show high EQE values of 11.0% and 5.5% with emission peaks at 477 and 467 nm, respectively. These achievements are enabled by a vapour-assisted crystallization technique, which largely mitigates local compositional heterogeneity and ion migration.

scholarly journals High-Efficiency, Broadband, Near Diffraction-Limited, Dielectric Metalens in Ultraviolet Spectrum

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 490 ◽  
Author(s):  
Saima Kanwal ◽  
Jing Wen ◽  
Binbin Yu ◽  
Dileep Kumar ◽  
Xu Chen ◽  
...  
Keyword(s):  
High Efficiency ◽  
Uv Light ◽  
Incident Light ◽  
Optical Devices ◽  
Photonic Devices ◽  
Ultraviolet Spectrum ◽  
Optical Systems ◽  
Optical Components ◽  
Discrete Phase ◽  
Phase Accumulation

Ultraviolet (UV) optical devices have plenteous applications in the fields of nanofabrication, military, medical, sterilization, and others. Traditional optical components utilize gradual phase accumulation phenomena to alter the wave-front of the light, making them bulky, expensive, and inefficient. A dielectric metasurface could provide an auspicious approach to precisely control the amplitude, phase, and polarization of the incident light by abrupt, discrete phase changing with high efficiency due to low absorption losses. Metalenses, being one of the most attainable applications of metasurfaces, can extremely reduce the size and complexity of the optical systems. We present the design of a high-efficiency transmissive UV metalens operating in a broadband range of UV light (250–400 nm) with outstanding focusing characteristics. The polarization conversion efficiency of the nano-rod unit and the focusing efficiency of the metasurface are optimized to be as high as 96% and 77%, respectively. The off-axis focusing characteristics at different incident angles are also investigated. The designed metalens that is composed of silicon nitride nanorods will significantly uphold the advancement of UV photonic devices and can provide opportunities for the miniaturization and integration of the UV nanophotonics and its applications.

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