scholarly journals Frontiers of light manipulation in natural, metallic, and dielectric nanostructures

2021 ◽  
Author(s):  
E. De Tommasi ◽  
E. Esposito ◽  
S. Romano ◽  
A. Crescitelli ◽  
V. Di Meo ◽  
...  
Keyword(s):  
Optical Sensors ◽  
High Performance ◽  
Field Enhancement ◽  
Cutting Edge ◽  
Optical Systems ◽  
Periodic Nanostructures ◽  
Light Manipulation ◽  
Propagation Of Light ◽  
Control Light ◽  
Spectral Ranges

AbstractThe ability to control light at the nanoscale is at the basis of contemporary photonics and plasmonics. In particular, properly engineered periodic nanostructures not only allow the inhibition of propagation of light at specific spectral ranges or its confinement in nanocavities or waveguides, but make also possible field enhancement effects in vibrational, Raman, infrared and fluorescence spectroscopies, paving the way to the development of novel high-performance optical sensors. All these devices find an impressive analogy in nearly-periodic photonic nanostructures present in several plants, animals and algae, which can represent a source of inspiration in the development and optimization of new artificial nano-optical systems. Here we present the main properties and applications of cutting-edge nanostructures starting from several examples of natural photonic architectures, up to the most recent technologies based on metallic and dielectric metasurfaces.

scholarly journals A microbiota–root–shoot circuit favours Arabidopsis growth over defence under suboptimal light

Nature Plants ◽  
2021 ◽  
Author(s):  
Shiji Hou ◽  
Thorsten Thiergart ◽  
Nathan Vannier ◽  
Fantin Mesny ◽  
Jörg Ziegler ◽  
...  
Keyword(s):  
Stress Responses ◽  
Photosynthetically Active Radiation ◽  
Bacterial Community Composition ◽  
Light Condition ◽  
Long Distance ◽  
Active Radiation ◽  
Light Manipulation ◽  
Growth Deficiency ◽  
Dependent Growth ◽  
Control Light

AbstractBidirectional root–shoot signalling is probably key in orchestrating stress responses and ensuring plant survival. Here, we show that Arabidopsis thaliana responses to microbial root commensals and light are interconnected along a microbiota–root–shoot axis. Microbiota and light manipulation experiments in a gnotobiotic plant system reveal that low photosynthetically active radiation perceived by leaves induces long-distance modulation of root bacterial communities but not fungal or oomycete communities. Reciprocally, microbial commensals alleviate plant growth deficiency under low photosynthetically active radiation. This growth rescue was associated with reduced microbiota-induced aboveground defence responses and altered resistance to foliar pathogens compared with the control light condition. Inspection of a set of A. thaliana mutants reveals that this microbiota- and light-dependent growth–defence trade-off is directly explained by belowground bacterial community composition and requires the host transcriptional regulator MYC2. Our work indicates that aboveground stress responses in plants can be modulated by signals from microbial root commensals.

Application Of Systems With Total Internal Reflection At Novosibirsk Free Electron Laser For Spectroscopy In The Terahertz Range

2016 ◽  
Vol 11 (3) ◽  
pp. 72-82
Author(s):  
Vasily Gerasimov ◽  
Elvira Grigorieva ◽  
Boris Knyazev ◽  
Yuliya Choporova
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Quantum Cascade Lasers ◽  
Attenuated Total Reflection ◽  
Terahertz Range ◽  
Optical Systems ◽  
Early Diagnosis Of Cancer ◽  
Infrared Spectral ◽  
Atr Spectroscopy ◽  
Spectral Ranges

Attenuated total reflection (ATR) spectroscopy is widely used in the visible and infrared spectral ranges. Progress in the development of laboratory scale monochromatic sources of terahertz radiation, such as quantum cascade lasers, suggests that in the near future this kind of spectrometers will be widely spread in the terahertz range. For this reason, the development of ATR based methods and devices is highly relevant. In this paper, we discuss the features of the use of ATR spectroscopy in the terahertz range, and describe some of the optical systems, designed for experiments at the Novosibirsk free electron laser (NovoFEL). We show that in the terahertz range the ATR spectroscopy has a number of significant advantages over the absorption spectroscopy. As an example, we are discussing the possibility of using terahertz polarimetry to develop a method for early diagnosis of cancer via the detection of left-handed to right-handed polysaccharide enantiomers ratio. Spectra of selected polysaccharides were recorded with a standard Fourier spectrometer using developed by us an ATR unit. The possibility of studying the polarization characteristics of polysaccharides in aqueous solutions using spectrally selective polarimeter with the NovoFEL as a tunable radiation source was demonstrated.

scholarly journals Application of Wireless Sensor Networks to Prevent the Spread of Forest Fires

2021 ◽  
Vol 11 (11) ◽  
pp. 199-203
Author(s):  
Le Quang Bon ◽  
Keyword(s):  
Wireless Sensor Network ◽  
Sensor Network ◽  
Optical Sensors ◽  
Forest Fires ◽  
Digital Camera ◽  
Partial Solution ◽  
Optical Systems ◽  
Wireless Sensor ◽  
Network Systems ◽  
Camera Systems

The objective of this article is to identify current trends and prospects for the use of technical facilities and installations to prevent the spread of wildfires by analyzing the literature. The analysis of the literature has allowed an analysis of different ground-based wildfire detection and monitoring systems: optical sensors and digital camera systems, and wireless sensor network systems. The author concludes that the wireless sensor network can be seen as a partial solution when used in combination with other technologies. Keywords—observation towers, optical systems, optical sensors, digital cameras, wireless sensor network.

Continuous measurement of pollution due to urban effluents under wet conditions using optical systems

1995 ◽  
Vol 32 (1) ◽  
pp. 241-247
Author(s):  
Gwenael Ruban
Keyword(s):  
Optical Sensors ◽  
Optical Systems ◽  
Sample Collection ◽  
Rainfall Events ◽  
Automation Systems ◽  
Calibration Sample ◽  
Long Time ◽  
Pollution Measurement ◽  
Measurement Validation ◽  
Better Than

Optical sensors appear well adapted to the pollution measurement of urban discharges during wet weather: they allow a continuous and long time investigation of sudden and highly variable phenomena such as rainfall events. They may also be connected to remote monitoring and sanitary equipment automation systems. This paper deals with the measurement principles and use of this type of equipment: adjustment and calibration, sample collection, equipment maintenance and measurement validation. Taking into account the hydraulicity (flow rate or velocity) allows one to improve appreciably the calibration for runoff waters. Calibration at the laboratory seems better than calibration using registered data on the field, as it makes it possible to eliminate the Suspended Matter under-estimation resulting from sampling/analysis.

SWIFTS: a groundbreaking integrated technology for high-performance spectroscopy and optical sensors

2013 ◽  
Author(s):  
Christophe Bonneville ◽  
Fabrice Thomas ◽  
Mikhael de Mengin Poirier ◽  
Etienne Le Coarer ◽  
Pierre Benech ◽  
...  
Keyword(s):  
Optical Sensors ◽  
High Performance ◽  
Integrated Technology

scholarly journals Deep Learning for Computational Mode Decomposition in Optical Fibers

2020 ◽  
Vol 10 (4) ◽  
pp. 1367
Author(s):  
Stefan Rothe ◽  
Qian Zhang ◽  
Nektarios Koukourakis ◽  
Jürgen W. Czarske
Keyword(s):  
Neural Network ◽  
Optical Fibers ◽  
High Performance ◽  
Deep Neural Network ◽  
Light Propagation ◽  
Training Data ◽  
Steady Increase ◽  
Cyberphysical Systems ◽  
Multimode Fibers ◽  
Propagation Of Light

Multimode fibers are regarded as the key technology for the steady increase in data rates in optical communication. However, light propagation in multimode fibers is complex and can lead to distortions in the transmission of information. Therefore, strategies to control the propagation of light should be developed. These strategies include the measurement of the amplitude and phase of the light field after propagation through the fiber. This is usually done with holographic approaches. In this paper, we discuss the use of a deep neural network to determine the amplitude and phase information from simple intensity-only camera images. A new type of training was developed, which is much more robust and precise than conventional training data designs. We show that the performance of the deep neural network is comparable to digital holography, but requires significantly smaller efforts. The fast characterization of multimode fibers is particularly suitable for high-performance applications like cyberphysical systems in the internet of things.

scholarly journals Lightning-Rod Effect of Plasmonic Field Enhancement on Hydrogen-Absorbing Transition Metals

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1235 ◽  
Author(s):  
Norihiko Fukuoka ◽  
Katsuaki Tanabe
Keyword(s):  
Transition Metals ◽  
Metal Surfaces ◽  
Noble Metals ◽  
Field Enhancement ◽  
Operating Conditions ◽  
Optical Systems ◽  
Field Energy ◽  
Enhancement Effect ◽  
Morphological Aspect ◽  
Aspect Ratios

The plasmonic enhancement of electromagnetic field energy density at the sharp tips of nanoparticles or nanoscale surface roughnesses of hydrogen-absorbing transition metals, Pd, Ti, and Ni, is quantitatively investigated. A large degree of energy focusing is observed for these transition metals in the microwave region, even surpassing the enhancement for noble metals according to the conditions. Pd, for instance, exhibits peak field enhancement factors of 6000 and 2 × 108 in air for morphological aspect ratios of 10 and 100, respectively. Metal surfaces possibly contain such degrees of nano- or micro-scale native random roughnesses, and, therefore, the field enhancement effect may have been unknowingly produced in existing electrical and optical systems. In addition, for future devices under development, particularly in hydrogen-related applications, it is desirable to design and optimize the systems, including the choice of materials, structures, and operating conditions, by accounting for the plasmonic local energy enhancement effect around the metal surfaces.

High Performance and Low Complexity Carrier Phase Recovery Schemes for 64-QAM Coherent Optical Systems

2017 ◽  
Author(s):  
Jaime Rodrigo Navarro ◽  
Aditya Kakkar ◽  
Richard Schatz ◽  
Xiaodan Pang ◽  
Oskars Ozolins ◽  
...  
Keyword(s):  
Carrier Phase ◽  
High Performance ◽  
Low Complexity ◽  
Optical Systems ◽  
Phase Recovery ◽  
Recovery Schemes
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