Design of Near Infrared Reflective Effective Pigment for LiDAR Detectable Paint

MRS Advances ◽  
2020 ◽  
Vol 5 (11) ◽  
pp. 515-522
Author(s):  
J. H. Kim ◽  
V. Patil ◽  
J. M. Chun ◽  
H. S. Park ◽  
S. W. Seo ◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
Autonomous Vehicles ◽  
Near Infrared ◽  
Light Detection And Ranging ◽  
Light Detection ◽  
Visible Absorption ◽  
Primary Sensor ◽  
Light Pulses ◽  
Nir Light ◽  
Dark Tone

ABSTRACTLight Detection and Ranging (LiDAR) is a primary sensor for autonomous vehicles to recognize surroundings. It detects near-infrared (NIR) light pulses, typically at 905nm, which is emitted and reflected by surrounding objects. Here, the fact of the matter is that conventional black or dark-tone cars with extremely low NIR reflection are hard to be detected by LiDAR and endanger the future highway. In this work, we propose to use platelet-shaped effect pigments with visible absorption and NIR reflectivity. Copper(Ⅱ) oxide and Silicon dioxide multilayer are theoretically investigated with different numbers of layers and thicknesses. The optimized structures appear various dark-tone colors with high NIR-reflectivity over 90%.

Light Detection and Carrier Transportation Mechanism in p-Type Si/n-Type Nanocrystalline FeSi2 Heterojunctions Produced via Radio-Frequency Magnetron Sputtering

2020 ◽  
Vol 20 (8) ◽  
pp. 5082-5088
Author(s):  
Pattarapol Sittisart ◽  
Nathaporn Promros ◽  
Rawiwan Chaleawpong ◽  
Peerasil Charoenyuenyao ◽  
Nattakorn Borwornpornmetee ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Leakage Current ◽  
Room Temperature ◽  
Near Infrared ◽  
Radio Frequency Magnetron Sputtering ◽  
Light Detection ◽  
Zero Bias ◽  
Nir Light ◽  
P Type ◽  
Carrier Transportation

In the current research, p-type Si/n-type nanocrystalline FeSi2 heterojunctions were fabricated at room temperature with an argon pressure of 2.66×10−1 Pa by means of the utilization of a radiofrequency magnetron sputtering technique. These heterojunctions were studied for the carrier transportation mechanism and near-infrared (NIR) light detection at various temperatures ranging from 300 K down to 150 K. At 300 K, the fabricated heterojunctions displayed a typical rectifying action together with substantial leakage current. At 150 K, the leakage current was clearly reduced by greater than four orders of magnitude. The value of the ideality factor (n) at 300 K was computed to be 1.87 and this was nearly constant under temperatures ranging from 300 down to 260 K. This implies that a recombination process was predominant. At temperatures lower than 250 K, the value of n was found to be more than 2. These results demonstrated that the carrier transportation mechanism was governed by a tunnelling process. A weak response for the irradiation of NIR light was observed at 300 K. At 150 K, the ratio of the photocurrent to the dark current evidently increased by more than two orders of magnitude. The detectivity at 150 K was 4.84×1010 cm Hz1/2 W−1 at zero bias voltage, which was clearly improved as compared to that at 300 K.

scholarly journals Analyzing the Angle Effect of Leaf Reflectance Measured by Indoor Hyperspectral Light Detection and Ranging (LiDAR)

2020 ◽  
Vol 12 (6) ◽  
pp. 919 ◽  
Author(s):  
Peilun Hu ◽  
Huaguo Huang ◽  
Yuwei Chen ◽  
Jianbo Qi ◽  
Wei Li ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Near Infrared ◽  
Specular Reflection ◽  
Incident Angle ◽  
Light Detection And Ranging ◽  
Light Detection ◽  
Leaf Reflectance ◽  
Data Registration ◽  
Angle Effect ◽  
Laser Pulse Intensity

Hyperspectral light detection and ranging (LiDAR) (HSL) combines the characteristics of hyperspectral imaging and LiDAR techniques into a single instrument without any data registration. It provides more information than hyperspectral imaging or LiDAR alone in the extraction of vegetation physiological and biochemical parameters. However, the laser pulse intensity is affected by the incident angle, and its effect on HSL has not yet been fully explored. It is important for employing HSL to investigate vegetation properties. The aim of this paper is to study the incident angle effect of leaf reflectance with HSL and build a model about this impact. In this paper, we studied the angle effect of leaf reflectance from indoor HSL measurements of individual leaves from four typical tree species in Beijing. We observed that (a) the increasing of incident angle decreases the leaf reflectance; (b) the leaf spectrum observed by HSL from 650 to 1000 nm with 10 nm spectral resolution (36 channels) are consistent with those that measured by Analytica Spectra Devices (ASD) spectrometer (R2 = 0.9472 ~ 0.9897); (c) the specular reflection is significant in the red bands, and clear non-Lambertian characteristics are observed. In the near-infrared, there is little specular reflection, but it follows the Lambert-scattering law. We divided the whole band (650–1000 nm) into six bands and established an empirical model to correct the influence of angle effect on the reflectance of the leaf for HSL applications. In the future, the calibration of HSL measurements applied for other targets will be studied by rigorous experiments and modelling.

scholarly journals Concurrent Firing Light Detection and Ranging System for Autonomous Vehicles

2021 ◽  
Vol 13 (9) ◽  
pp. 1767
Author(s):  
Gunzung Kim ◽  
Imran Ashraf ◽  
Jeongsook Eom ◽  
Yongwan Park
Keyword(s):  
Laser Pulse ◽  
Autonomous Vehicles ◽  
Measuring Method ◽  
Light Detection And Ranging ◽  
Walking Robots ◽  
Lidar System ◽  
Light Detection ◽  
Emission Channel ◽  
Scanning Lidar ◽  
Pulse Stream

We proposed a light detection and ranging (LIDAR) system that changes the measurement strategy from a LIDAR system of sequential emission and measuring method to a concurrent firing measuring method. The proposed LIDAR was a 3D scanning LIDAR method that consisted of 128 output channels in one vertical line in the measurement direction and concurrently measured the distance for each of these 128 channels. The scanning LIDAR emitted 128 laser pulse streams encoded by carrier-hopping prime code (CHPC) technology with identification and checksum. When the reflected pulse stream was received and demodulated, the emission channel could be recognized. This information could be used to estimate the time when the laser pulse stream was emitted and calculate the distance to the object reflecting the laser. By using the identification of the received reflected wave, even if several positions were measured at the same time, the measurement position could be recognized after the reception. Extensive simulations indicated that the proposed LIDAR could provide autonomous vehicles or autonomous walking robots with good distance images to recognize the environment ahead.

Catalyst Halogenation Enables Rapid and Efficient Polymerizations with Visible to Near-Infrared Light

2020 ◽  
Author(s):  
Alex Stafford ◽  
Dowon Ahn ◽  
Emily Raulerson ◽  
Kun-You Chung ◽  
Kaihong Sun ◽  
...  
Keyword(s):  
Near Infrared ◽  
Transient Absorption ◽  
Reaction Times ◽  
Infrared Light ◽  
Structure Property ◽  
Light Emitting ◽  
Structure Property Relationships ◽  
Nir Light ◽  
Light Intensities ◽  
Emission Quenching

Driving rapid polymerizations with visible to near-infrared (NIR) light will enable nascent technologies in the emerging fields of bio- and composite-printing. However, current photopolymerization strategies are limited by long reaction times, high light intensities, and/or large catalyst loadings. Improving efficiency remains elusive without a comprehensive, mechanistic evaluation of photocatalysis to better understand how composition relates to polymerization metrics. With this objective in mind, a series of methine- and aza-bridged boron dipyrromethene (BODIPY) derivatives were synthesized and systematically characterized to elucidate key structure-property relationships that facilitate efficient photopolymerization driven by visible to NIR light. For both BODIPY scaffolds, halogenation was shown as a general method to increase polymerization rate, quantitatively characterized using a custom real-time infrared spectroscopy setup. Furthermore, a combination of steady-state emission quenching experiments, electronic structure calculations, and ultrafast transient absorption revealed that efficient intersystem crossing to the lowest excited triplet state upon halogenation was a key mechanistic step to achieving rapid photopolymerization reactions. Unprecedented polymerization rates were achieved with extremely low light intensities (< 1 mW/cm<sup>2</sup>) and catalyst loadings (< 50 μM), exemplified by reaction completion within 60 seconds of irradiation using green, red, and NIR light-emitting diodes.

Bi19S27I3 nanorods: a new candidate for photothermal therapy in the first and second biological near-infrared windows

Nanoscale ◽  
2021 ◽  
Author(s):  
Jinsong Xiong ◽  
Qinghuan Bian ◽  
Shuijin Lei ◽  
Yatian Deng ◽  
Kehan Zhao ◽  
...  
Keyword(s):  
Cancer Therapy ◽  
Photothermal Therapy ◽  
Near Infrared ◽  
Research Interest ◽  
The Past ◽  
Nir Light ◽  
Considerable Research ◽  
Key Factor

Near-infrared (NIR) light induced photothermal cancer therapy using nanomaterials as photothermal agents has attracted considerable research interest over the past few years. As the key factor in the photothermal therapy...

scholarly journals Near-Infrared-Triggered Upconverting Nanoparticles for Biomedicine Applications

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 756
Author(s):  
Manoj Kumar Mahata ◽  
Ranjit De ◽  
Kang Taek Lee
Keyword(s):  
Drug Delivery ◽  
Photothermal Therapy ◽  
Near Infrared ◽  
Cutting Edge ◽  
Clinical Translation ◽  
Basic Knowledge ◽  
Nanotechnology Research ◽  
Nir Light

Due to the unique properties of lanthanide-doped upconverting nanoparticles (UCNP) under near-infrared (NIR) light, the last decade has shown a sharp progress in their biomedicine applications. Advances in the techniques for polymer, dye, and bio-molecule conjugation on the surface of the nanoparticles has further expanded their dynamic opportunities for optogenetics, oncotherapy and bioimaging. In this account, considering the primary benefits such as the absence of photobleaching, photoblinking, and autofluorescence of UCNPs not only facilitate the construction of accurate, sensitive and multifunctional nanoprobes, but also improve therapeutic and diagnostic results. We introduce, with the basic knowledge of upconversion, unique properties of UCNPs and the mechanisms involved in photon upconversion and discuss how UCNPs can be implemented in biological practices. In this focused review, we categorize the applications of UCNP-based various strategies into the following domains: neuromodulation, immunotherapy, drug delivery, photodynamic and photothermal therapy, bioimaging and biosensing. Herein, we also discuss the current emerging bioapplications with cutting edge nano-/biointerfacing of UCNPs. Finally, this review provides concluding remarks on future opportunities and challenges on clinical translation of UCNPs-based nanotechnology research.

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