Spatial multiplexing holographic combiner for glasses-free augmented reality

<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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Subwavelength sorting of full-color based on anti-Hermitian metasurfaces

Nanophotonics ◽

10.1515/nanoph-2020-0526 ◽

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.

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Aminophosphine Reduction Mechanisms and the Synthesis of Indium Phosphide Nanomaterials

10.26686/wgtn.17136626 ◽

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

RSC Advances ◽

10.1039/c8ra07657j ◽

2018 ◽

Vol 8 (68) ◽

pp. 38935-38940 ◽

Cited By ~ 5

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.

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Augmented Reality Vector Light Field Display with Large Viewing Distance Based on Pixelated Multilevel Blazed Gratings

Photonics ◽

10.3390/photonics8080337 ◽

2021 ◽

Vol 8 (8) ◽

pp. 337

Author(s):

Jiacheng Shi ◽

Jianyu Hua ◽

Fengbin Zhou ◽

Min Yang ◽

Wen Qiao

Keyword(s):

Augmented Reality ◽

Light Field ◽

Motion Parallax ◽

Viewing Distance ◽

Viewing Angle ◽

Entertainment Education ◽

3D Objects ◽

Natural Motion ◽

3D Scene ◽

Occlusion Effect

Glasses-free augmented reality (AR) 3D display has attracted great interest in its ability to merge virtual 3D objects with real scenes naturally, without the aid of any wearable devices. Here we propose an AR vector light field display based on a view combiner and an off-the-shelf purchased projector. The view combiner is sparsely covered with pixelated multilevel blazed gratings (MBG) for the projection of perspective virtual images. Multi-order diffraction of the MBG is designed to increase the viewing distance and vertical viewing angle. In a 20-inch prototype, multiple sets of 16 horizontal views form a smooth parallax. The viewing distance of the 3D scene is larger than 5 m. The vertical viewing angle is 15.6°. The light efficiencies of all views are larger than 53%. We demonstrate that the displayed virtual 3D scene retains natural motion parallax and high brightness while having a consistent occlusion effect with natural objects. This research can be extended to applications in areas such as human–computer interaction, entertainment, education, and medical care.

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A Fast and Realistic Bloom Rendering Method for Large Scale 3D Scene

2021 11th International Conference on Information Science and Technology (ICIST) ◽

10.1109/icist52614.2021.9440634 ◽

2021 ◽

Author(s):

WenShan Fan

Keyword(s):

Large Scale ◽

3D Scene

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System design for inferring colony-level pollination activity through miniature bee-mounted sensors

Scientific Reports ◽

10.1038/s41598-021-82537-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Haron M. Abdel-Raziq ◽

Daniel M. Palmer ◽

Phoebe A. Koenig ◽

Alyosha C. Molnar ◽

Kirstin H. Petersen

Keyword(s):

Data Acquisition ◽

Honey Bees ◽

Large Scale ◽

Physical World ◽

Cluttered Environments ◽

Robotic Mapping ◽

Large Scale Data ◽

Trade Offs ◽

Large Numbers ◽

Engineered Systems

AbstractIn digital agriculture, large-scale data acquisition and analysis can improve farm management by allowing growers to constantly monitor the state of a field. Deploying large autonomous robot teams to navigate and monitor cluttered environments, however, is difficult and costly. Here, we present methods that would allow us to leverage managed colonies of honey bees equipped with miniature flight recorders to monitor orchard pollination activity. Tracking honey bee flights can inform estimates of crop pollination, allowing growers to improve yield and resource allocation. Honey bees are adept at maneuvering complex environments and collectively pool information about nectar and pollen sources through thousands of daily flights. Additionally, colonies are present in orchards before and during bloom for many crops, as growers often rent hives to ensure successful pollination. We characterize existing Angle-Sensitive Pixels (ASPs) for use in flight recorders and calculate memory and resolution trade-offs. We further integrate ASP data into a colony foraging simulator and show how large numbers of flights refine system accuracy, using methods from robotic mapping literature. Our results indicate promising potential for such agricultural monitoring, where we leverage the superiority of social insects to sense the physical world, while providing data acquisition on par with explicitly engineered systems.

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Motion Parallax Representation for Indirect Augmented Reality

2016 IEEE International Symposium on Mixed and Augmented Reality (ISMAR-Adjunct) ◽

10.1109/ismar-adjunct.2016.0051 ◽

2016 ◽

Cited By ~ 1

Author(s):

Fumio Okura ◽

Yuya Nishizaki ◽

Tomokazu Sato ◽

Norihiko Kawai ◽

Naokazu Yokoya

Keyword(s):

Augmented Reality ◽

Motion Parallax

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Exploiting Proximity-Based Mobile Apps for Large-Scale Location Privacy Probing

Security and Communication Networks ◽

10.1155/2018/3182402 ◽

2018 ◽

Vol 2018 ◽

pp. 1-22 ◽

Cited By ~ 1

Author(s):

Shuang Zhao ◽

Xiapu Luo ◽

Xiaobo Ma ◽

Bo Bai ◽

Yankang Zhao ◽

...

Keyword(s):

Social Networks ◽

Case Studies ◽

Real World ◽

Emission Reduction ◽

Large Scale ◽

Location Privacy ◽

Mobile Apps ◽

Physical World ◽

Typical Type ◽

Location Spoofing

Proximity-based apps have been changing the way people interact with each other in the physical world. To help people extend their social networks, proximity-based nearby-stranger (NS) apps that encourage people to make friends with nearby strangers have gained popularity recently. As another typical type of proximity-based apps, some ridesharing (RS) apps allowing drivers to search nearby passengers and get their ridesharing requests also become popular due to their contribution to economy and emission reduction. In this paper, we concentrate on the location privacy of proximity-based mobile apps. By analyzing the communication mechanism, we find that many apps of this type are vulnerable to large-scale location spoofing attack (LLSA). We accordingly propose three approaches to performing LLSA. To evaluate the threat of LLSA posed to proximity-based mobile apps, we perform real-world case studies against an NS app named Weibo and an RS app called Didi. The results show that our approaches can effectively and automatically collect a huge volume of users’ locations or travel records, thereby demonstrating the severity of LLSA. We apply the LLSA approaches against nine popular proximity-based apps with millions of installations to evaluate the defense strength. We finally suggest possible countermeasures for the proposed attacks.

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