scholarly journals Subwavelength sorting of full-color based on anti-Hermitian metasurfaces

Nanophotonics ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 967-974
Author(s):  
Seong Jun Kim ◽  
Changhyun Lee ◽  
Sangtae Jeon ◽  
Junghyun Park ◽  
Soo Jin Kim
Keyword(s):  
Optical Sensors ◽  
Detection System ◽  
Incident Light ◽  
Practical Interest ◽  
Target Position ◽  
Visible Spectrum ◽  
Color Filter ◽  
Full Color ◽  
Spectral Linewidth ◽  
Entire Visible Spectrum

AbstractSplitting the spectrum of incident light at nanoscale has been of great scientific and practical interest due to its potential application in various optical sensors. For many years, researchers have been striving to realize the full-color sorting of light at subwavelength scale, while keeping the loss of incident photons to a minimum. In this article, we present semiconductor-based metasurfaces that facilitate the efficient sorting of full-color by inducing anti-Hermitian coupling between multiple nanoantenna arrays. To achieve this, we first explore how the coherent interactions between maximally crafted nanoantennas in the metasurfaces can be effectively controlled by judiciously positioning them in both lateral and vertical directions, which leads to the switched coupling of light at each target position. Based on the analysis, we demonstrate a metasurface-based absorber that features efficient, spectropolarimetric detections over the entire visible spectrum, ranging from 470 to 630 nm. In addition, the metasurface detects relatively narrow spectral linewidth of 60 nm and shows the sensitivity up to 70%, which surpasses the previous works on subwavelength photon sorting or color filter-based detection system. We envision that our approach provides guidelines for realizing the metasurfaces with enhanced functionalities, that is the increase of spectral channels for detection in a given subwavelength-scaled unit cell.

scholarly journals Spatial multiplexing holographic combiner for glasses-free augmented reality

Nanophotonics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 3003-3010
Author(s):  
Jiacheng Shi ◽  
Wen Qiao ◽  
Jianyu Hua ◽  
Ruibin Li ◽  
Linsen Chen
Keyword(s):  
Augmented Reality ◽  
Large Scale ◽  
Motion Parallax ◽  
Visible Spectrum ◽  
Physical World ◽  
Spatial Multiplexing ◽  
White Balance ◽  
Full Color ◽  
Entire Visible Spectrum ◽  
3D Scene

AbstractGlasses-free augmented reality is of great interest by fusing virtual 3D images naturally with physical world without the aid of any wearable equipment. Here we propose a large-scale spatial multiplexing holographic see-through combiner for full-color 3D display. The pixelated metagratings with varied orientation and spatial frequency discretely reconstruct the propagating lightfield. The irradiance pattern of each view is tailored to form super Gaussian distribution with minimized crosstalk. What’s more, spatial multiplexing holographic combiner with customized aperture size is adopted for the white balance of virtually displayed full-color 3D scene. In a 32-inch prototype, 16 views form a smooth parallax with a viewing angle of 47°. A high transmission (>75%) over the entire visible spectrum range is achieved. We demonstrated that the displayed virtual 3D scene not only preserved natural motion parallax, but also mixed well with the natural objects. The potential applications of this study include education, communication, product design, advertisement, and head-up display.

scholarly journals Near-zero reflection of all-dielectric structural coloration enabling polarization-sensitive optical encryption with enhanced switchability

Nanophotonics ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 919-926
Author(s):  
Chunghwan Jung ◽  
Younghwan Yang ◽  
Jaehyuck Jang ◽  
Trevon Badloe ◽  
Taejun Lee ◽  
...  
Keyword(s):  
Incident Light ◽  
Visible Spectrum ◽  
Qr Code ◽  
Structural Coloration ◽  
Optical Encryption ◽  
Full Color ◽  
Potential Applications ◽  
Color Spectrum ◽  
Color Printing ◽  
Security Information

AbstractStructural coloration using metasurfaces has been steadily researched to overcome the limitations of conventional color printing using pigments by improving the resolution, lowering the toxicity, and increasing the durability. Many metasurfaces have been demonstrated for dynamic structural coloration to convert images at the visible spectrum. However, the previous works cannot reach near-zero scattering when colors are turned-off, preventing it from being cryptographic applications. Herein, we propose a completely on/off switchable structural coloration with polarization-sensitive metasurfaces, enabling full-colored images to be displayed and hidden through the control of the polarization of incident light. It is confirmed that the nanostructure exhibits the polarization-dependent magnetic field distributions, and near-zero scattering is realized when the polarization of incident light is perpendicular to the long axis of the nanofins. Also, the metasurfaces are made up of triple-nanofin structures whose lengths affect locations of resonance peaks, resulting in full-color spectrum coverages. With such advantages, a QR code image, a two-color object image, and an overlapped dual-portrait image are obtained with the metasurfaces. Such demonstrations will provide potential applications in the fields of high-security information encryption, security tag, multichannel imaging, and dynamic displays.

scholarly journals Efficient visible-light full-color tuning of self-organized helical superstructures enabled by fluorinated chiral switches

RSC Advances ◽  
2018 ◽  
Vol 8 (68) ◽  
pp. 38935-38940 ◽  
Author(s):  
Lang Qin ◽  
Wei Gu ◽  
Yingying Chen ◽  
Jia Wei ◽  
Yanlei Yu
Keyword(s):  
Liquid Crystals ◽  
Visible Light ◽  
Blue Light ◽  
Visible Spectrum ◽  
Cholesteric Liquid Crystals ◽  
Color Tuning ◽  
Dynamic Tuning ◽  
Full Color ◽  
Self Organized ◽  
Entire Visible Spectrum

Reversible dynamic tuning of the reflection color from cholesteric liquid crystals within the entire visible spectrum is driven by green and blue light via newly designed chiral switches.

scholarly journals Microfabrication and Surface Functionalization of Soda Lime Glass through Direct Laser Interference Patterning

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 129
Author(s):  
Marcos Soldera ◽  
Sabri Alamri ◽  
Paul Alexander Sürmann ◽  
Tim Kunze ◽  
Andrés Fabián Lasagni
Keyword(s):  
Laser Radiation ◽  
Surface Functionalization ◽  
Incident Light ◽  
Chemical Properties ◽  
Visible Spectrum ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Textured Surfaces ◽  
Aspect Ratios ◽  
Direct Laser

All-purpose glasses are common in many established and emerging industries, such as microelectronics, photovoltaics, optical components, and biomedical devices due to their outstanding combination of mechanical, optical, thermal, and chemical properties. Surface functionalization through nano/micropatterning can further enhance glasses’ surface properties, expanding their applicability into new fields. Although laser structuring methods have been successfully employed on many absorbing materials, the processability of transparent materials with visible laser radiation has not been intensively studied, especially for producing structures smaller than 10 µm. Here, interference-based optical setups are used to directly pattern soda lime substrates through non-lineal absorption with ps-pulsed laser radiation in the visible spectrum. Line- and dot-like patterns are fabricated with spatial periods between 2.3 and 9.0 µm and aspect ratios up to 0.29. Furthermore, laser-induced periodic surface structures (LIPSS) with a feature size of approximately 300 nm are visible within these microstructures. The textured surfaces show significantly modified properties. Namely, the treated surfaces have an increased hydrophilic behavior, even reaching a super-hydrophilic state for some cases. In addition, the micropatterns act as relief diffraction gratings, which split incident light into diffraction modes. The process parameters were optimized to produce high-quality textures with super-hydrophilic properties and diffraction efficiencies above 30%.

scholarly journals Spectroscopic detection of forest diseases: a review (1970–2020)

2021 ◽  
Author(s):  
Lorenzo Cotrozzi
Keyword(s):  
Early Detection ◽  
Optical Sensors ◽  
Near Infrared ◽  
Sustainable Forest Management ◽  
Visible Spectrum ◽  
Cost Effective ◽  
Infrared Region ◽  
Forest Disturbances ◽  
Effective Manner ◽  
Forest Diseases

AbstractSustainable forest management is essential to confront the detrimental impacts of diseases on forest ecosystems. This review highlights the potential of vegetation spectroscopy in improving the feasibility of assessing forest disturbances induced by diseases in a timely and cost-effective manner. The basic concepts of vegetation spectroscopy and its application in phytopathology are first outlined then the literature on the topic is discussed. Using several optical sensors from leaf to landscape-level, a number of forest diseases characterized by variable pathogenic processes have been detected, identified and quantified in many country sites worldwide. Overall, these reviewed studies have pointed out the green and red regions of the visible spectrum, the red-edge and the early near-infrared as the spectral regions most sensitive to the disease development as they are mostly related to chlorophyll changes and symptom development. Late disease conditions particularly affect the shortwave-infrared region, mostly related to water content. This review also highlights some major issues to be addressed such as the need to explore other major forest diseases and geographic areas, to further develop hyperspectral sensors for early detection and discrimination of forest disturbances, to improve devices for remote sensing, to implement long-term monitoring, and to advance algorithms for exploitation of spectral data. Achieving of these goals will enhance the capability of vegetation spectroscopy in early detection of forest stress and in managing forest diseases.

scholarly journals Rhodanine-based dyes absorbing in the entire visible spectrum

2017 ◽  
Vol 4 (6) ◽  
pp. 1024-1028 ◽  
Author(s):  
Rafael Sandoval-Torrientes ◽  
Joaquín Calbo ◽  
David García-Fresnadillo ◽  
José Santos ◽  
Enrique Ortí ◽  
...  
Keyword(s):  
Optical Properties ◽  
Dft Calculations ◽  
Electrochemical Characterizations ◽  
Visible Spectrum ◽  
Electronic And Optical Properties ◽  
Entire Visible Spectrum

A series of new broad-absorbing rhodanine-fluorene dyes conjugated with triarylamines are presented. Spectroscopic and electrochemical characterizations, along with theoretical DFT calculations, unveil the electronic and optical properties of the dyes.

A new thermal infrared and visible spectrum images-based pedestrian detection system

2018 ◽  
Vol 78 (12) ◽  
pp. 15861-15885 ◽  
Author(s):  
Redouan Lahmyed ◽  
Mohamed El Ansari ◽  
Ayoub Ellahyani
Keyword(s):  
Detection System ◽  
Pedestrian Detection ◽  
Visible Spectrum ◽  
Thermal Infrared

scholarly journals DIGITAL IMAGE ANALYSIS OF THE VISIBLE REGION THROUGH SIMULATION OF ROCK ART PAINTINGS

2016 ◽  
Author(s):  
Berta Carrión-Ruiz ◽  
Silvia Blanco-Pons ◽  
Jose Luis Lerma
Keyword(s):  
Rock Art ◽  
Visible Region ◽  
Visible Spectrum ◽  
Principal Component ◽  
Optical Filters ◽  
Visible Range ◽  
Redundant Data ◽  
The Difference ◽  
Entire Visible Spectrum ◽  
New Research

Non-destructive rock art recording techniques are getting special attention in the last years, opening new research lines in order to improve the level of documentation and understanding of our rich legacy. This paper applies the principal component analysis (PCA) technique in images that include wavelengths between 400-700 nm (visible  range). Our approach is focused on determining the difference provided by the image processing of the visible region through four spectral images versus an image that encompasses the entire visible spectrum. The images were taken by means of optical filters that take specific wavelengths and exclude parts of the spectrum. Simulation of rock art is prepared in laboratory. For this purpose, three different pigments were made simulating the material composition of rock art paintings. The advantages of studying the visible spectrum in separate images are analysed. In addition, PCA is applied to each of the images to reduce redundant data. Finally, PCA is applied to the image that contains the entire visible spectrum and is compared with previous results. Through the results of the four visible spectral images one can begin to draw conclusions about constituent painting materials without using decorrelation techniques.

scholarly journals Accurate and Efficient Representation of Obstacles Using Radar Visualizer

2021 ◽  
Vol 9 (VI) ◽  
pp. 4429-4431
Author(s):  
K. Akanksha
Keyword(s):  
Detection System ◽  
Target Position ◽  
Radar System ◽  
Motor Vehicles ◽  
Radio Waves ◽  
Receiving Antenna ◽  
Efficient Representation ◽  
Transmitting Antenna ◽  
Analyze Data

Radar is a detection system that uses radio waves to determine the range, angle or velocity of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. A radar system consist of a transmitting antenna, a receiving antenna (often same antenna is used for transmitting and receiving) and a receiver and process to determine properties of the objects. In our project we are detecting the target position of the obstacles that come in our way be it in military, aircrafts, ships, clouds, etc. using MATLAB. Using MATLAB, you can: analyze data, develop algorithms, create models and applications. The language, apps, and build in math functions enable you to quickly explore multiple approaches to arrive at a solution. Using MATLAB and Simulink we are doing radar visualizer.

scholarly journals Aminophosphine Reduction Mechanisms and the Synthesis of Indium Phosphide Nanomaterials

2021 ◽  
Author(s):  
◽  
Geoffry Laufersky
Keyword(s):  
Indium Phosphide ◽  
Density Functional ◽  
Large Scale ◽  
Visible Spectrum ◽  
Size Dependent ◽  
Reduction Mechanisms ◽  
Highly Sensitive ◽  
Dependent Absorption ◽  
Entire Visible Spectrum ◽  
The Impact

<p>Indium phosphide (InP) nanomaterials are attractive for countless technological applications due to their well-placed band gap energies. The quantum confinement of these semiconductors can give rise to size-dependent absorption and emission features throughout the entire visible spectrum. Therefore, InP materials can be employed as low-toxicity fluorophores that can be implemented in high value avenues such as biological probes, lighting applications, and lasing technologies. However, large scale development of these quantum dots (QDs) has been stymied by the lack of affordable and safe phosphorus precursors. Syntheses have largely been restricted to the use of dangerous chemicals such as tris(trimethylsilyl)phosphine ((TMS)₃P), which is costly and highly sensitive to oxygen and water. Recently, less-hazardous tris(dialkylamino)phosphines have been introduced to produce InP QDs on par with those utilizing (TMS)₃P. However, a poor understanding of the reaction mechanics has resulted in difficulties tuning and optimizing this method.  In this work, density functional theory (DFT) is used to identify the mechanism of this aminophosphine precursor conversion. This understanding is then implemented to design an improved InP QD synthesis, allowing for the production of high-quality materials outside of glovebox conditions. Time is spent understanding the impact of different precursor salts on the reaction mechanisms and discerning their subsequent effects on nanoparticle size and quality. The motivation of this work is to formulate safer and less technical indium phosphide quantum dot syntheses to foster non-specialist and industrial implementation of these materials.</p>

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