Light Transmission Characteristics Research Articles

Entangled Optical Quantum Imaging Method Assisted by AUVs Based on Underwater Light Transmission Characteristics

Entangled Optical Quantum Imaging Method Assisted by AUVs Based on Underwater Light Transmission Characteristics

Graphene oxide based plasmonic nano-cavity sensor for high-performance refractive index sensing

Abstract In this work, a nano-cavity based metal-insulator-metal structure is proposed which can be used as a high-performance refractive index sensor. The analysis of its sensing capabilities is done by determining the transmission characteristics of light through the insulating air channel between the metal layer. The loss in transmission in this channel is indicative of light leaking out of it and portion of it getting coupled to nano-cavities considered in the metal layers on both sides of the air channel. The analyte, whose refractive index is to be sensed, is kept in these nano-cavities. The basic structure is modified by introducing graphene oxide (GO) on the inner wall of the nano-cavity, which further improves the confinement of light in the nano-cavities. It is also shown that increasing the number of nano-cavity duos enhances the transmission loss through the waveguide and as a result the light energy confinement in the cavity increases. Calculated values of sensitivities and Figure of Merit of the proposed sensor structure are much higher than similar works done previously. The uniqueness of the work is two-fold; namely use of graphene oxide as an inner layer of the nano-cavity improves the sensitivity of the sensor and secondly calculating the waveguide transmission to indirectly determine the confinement of light energy in nano-cavity simplifies the analysis of the performance of the proposed sensor. The structure is simple and can be easily fabricated using a standard fabrication process.

금속 막 상의 나노 슬릿구조에서의 광 투과 특성 분석

금속 막 상의 나노 슬릿구조에서의 광 투과 특성 분석

Double Resonance Characteristic of Photonic Crystal Structure with Defect Metal Layer

The optical response of the photonic crystal structure has been analyzed using the Finite Difference Frequency Domain (FDFD) method. Simulation using this method aims to analyze the characteristics of light transmission when interacting with related structure. The results of the study of photonic crystal structures with two defects show that there are two transmittance bands called double resonances at two specific wavelengths. Changes in the resonance peak with respect to the variations of refractive index in the second defect layer resulted in a linear change with significant sensitivity. For photonic crystals with two defects, the first defect is a metal layer and the second defect is material sensing, which produces double resonance with a sensitivity of 7,825 and 3,2675, while for photonic crystals with the first defect, a dielectric layer, and the second defect is material sensing, produces single resonance with a sensitivity of 2,022. The choice of the first defect is that the metal layer is quite important, in addition to producing greater sensitivity, it also produces a field enhancement between the dielectric and the metal layer which is called surface plasmon resonance (SPR). The sensitivity value can also be set by determining the thickness of the second defect layer. These results can be used as a standard for fabrication and developed for sensor applications.

Flame Retardant Additives in Polylactic Acid (PLA) Photopolymer Resin for 3D Printing Digital Light Processing (DLP)

Digital light processing (DLP) technology has been developed based on stereolithography (SLA) 3D-printing principle. The biodegradable and low-cost polylactic-acid (PLA) has so far been used as polymeric material for photopolymer resin in SLA and DLP. To achieve functional SLA-processed product, the properties of such PLA has been improved, with the aim to make it flame retardant, less viscous, and having light transmittance characteristics. In this study, the liquid raw PLA photopolymer was changed by adding different contents of Ammonium Phosphate (APP), melamine cyanurate (MCA), Aluminum Tri-hydroxide (Al2O3) and Nano-silicon dioxide (SiO2) additives. The solid PLA nanocomposite specimens were printed by using DLP device according to the standard geometry for burning test UL-94 to evaluate its flame-retardant property. In addition, the printing product and residue after burning test was analyzed for their morphological characteristic by using SEM. The results showed that the low weight fraction of MCA showed excellent performance. PLA/MCA successfully kept green body form until the sintering temperature of stainless steel was achieved. It can become a reference for application DLP 3D printing products in the casting and sintering process.

Laser forward and backward scattering characteristics and experimental study of bubbles in ship wake.

The detection and tracking of ships can be realized by using the laser forward and backward scattering characteristics of ship wake bubbles. In this paper, the detection ability of two kinds of scattering to wake bubbles is studied. Based on the distribution characteristics of ship wake and bubble targets, typical bubble targets are selected to study from both micro and macro aspects. The light scattering model of water is established from the microscopic aspect, and the forward and backward scattering light intensity equations of water are derived. The circumferential scattering characteristics of a single bubble are analyzed based on the Mie scattering theory. According to the transmission characteristics of light in wake bubbles, the secondary scattering model of wake bubbles is established, and the forward and backward scattering light intensity equations are derived. In the macroscopic aspect, the laser scattering simulation model of wake bubbles is established by Monte Carlo, and the forward and backward scattering characteristics of wake bubble clusters with different radii, densities, and thicknesses are analyzed emphatically. A laser forward scattering and backscattering detection system under typical bubble characteristics was built, and the composite scattering characteristics of wake bubbles with different parameter characteristics were experimentally analyzed. The theoretical and experimental results show that with the increase of bubble radius, density, and thickness, the amplitude of laser forward scattering signal of bubble groups decreases gradually, the amplitude of backward scattering signal increases gradually, the change rate of forward and backward scattering amplitude increases, and the change rate of backscattering is obviously larger than that of forward scattering. The detection of wake bubbles by backscattering has more characteristic changes than that by forward scattering, and the detection success rate is higher. The research results can provide theoretical and experimental support for the design of a ship wake laser detection system.

Two-particle quantum walk on graphene structure graph

Graphene, a new material with a hexagonal honeycomb sheet structure composed of a single layer of carbon atoms, is the world's thinnest and strongest substance known to human, it has low resistivity and strong light transmission characteristics, so it can be used as a candidate material for integrated circuit chips and new energy batteries. In this paper, we mainly discuss the quantum walk of two non-interacting particles on the graphene structure graph, in which we select coin operator G in coin space HC and construct shift operator S, the time evolution operator U is obtained from the tensor of G and S. Since two particles without interaction can occupy the same site, the initial state is a composite of two particles at the same site. On this foundation, the relation between the relative distance and evolution time of two non-interacting particles is studied by the distance evolution operator.

Unidirectional reflectionless propagation in borophene plasmonic metamaterials

We propose a nonreciprocal borophene metamaterial consisting of a longitudinally separated array of double-layer borophene nanoribbons (BNRs) suspended in the air, exhibiting the unidirectional reflectionless properties at exceptional points (EPs) in the near-infrared communication band. Based on the coupled mode theory and the transfer matrix method, the transmission characteristics of light in the proposed structure can be effectively described. The internal loss and radioactive loss factors of the plasmonic system are successfully calculated by employing the theoretical model we proposed. Thus we conduct the analytical description of the unidirectional reflectionless phenomenon between two borophene plasmonic resonators, where the analytical results show excellent consistency with the finite-difference time-domain simulations. Different from the waveguide structure, the proposed structure has better adjustability that the regulation of EPs can be dynamically achieved by manipulating carrier density and the spatial separation between double-layer of BNRs. Our research results possess the possibility for promising application in tunable nanoelectronic devices in the communication band.

Design of an Ultra-Wideband Transparent Wave Absorber.

In this paper, a multilayer ultra-wideband transparent metamaterial wave absorber is proposed, which has the characteristics of ultra-wideband wave absorption, light transmission and flexible bending; in addition, due to the complete symmetry of the structure, the absorber has polarization insensitivity to incident electromagnetic waves. Both simulation and experimental results show that the frequency range of the microwave absorption rate is higher than 90% between 8.7 GHz and 38.9 GHz (between which most of the absorption rate can reach more than 95%), the total bandwidth is 30.2 GHz, and the relative bandwidth is 126.9%, realizing microwave broadband absorption and covering commonly used communication frequency bands such as X-band, Ku-band, and K-band. A sample was processed and tested. The test results are in good agreement with the results of the theoretical analysis, which proves the correctness of the theoretical analysis. In addition, through the selection and oxidation of indium tin (ITO) materials, the metamaterial also has the characteristics of optical transparency and flexibility, so it has potential application value in the window radar stealth and conformal radar stealth of weapons and equipment.

Sustainable Greenhouse Covering Materials with Nano- and Micro-Particle Additives for Enhanced Radiometric and Thermal Properties and Performance

This review aims to provide a comprehensive overview of nano- and microscopic materials that can provide thermal radiation insulation without reducing visible light transmittance, thereby reducing heat loss and conserving energy in greenhouses. We also reviewed the radial and thermal properties of greenhouse covering materials. Fillers, colorants, reinforcers, and additives, as well as glass, plastic film, and plastic sheet materials, were discussed. Additionally, by searching for keywords like insulation film, insulation agent, and infrared insulation, compounds based on graphene and fullerene as well as phase transition materials (PCMs) that may be used for radiation insulation, we proposed their potential use in greenhouse covers. They can be divided into semi-transparent photovoltaic (PV) materials, zinc oxide-based film fillers, and silica filter films. We discussed the radiation heat insulation and light transmission characteristics of these materials. Nano-synthesis techniques were also investigated. Based on latest advances in the literature, future developments in the micro- and macroscale synthesis of nanomaterials will enable additional innovations in covering materials for greenhouse structures. A limiting factor, though, was the high sensitivity of PVs to external climatic and meteorological variables. The ability of materials used to make greenhouse covers to control the microclimate, reduce CO2 emissions, use less energy, and increase agricultural productivity, however, cannot be disputed. Similar to this, a thorough examination of the uses of various greenhouse technologies reveals that the advancements also have financial advantages, particularly in terms of reducing greenhouse heating and cooling expenses. The PCMs, which decreased greenhouse-operating costs by maintaining constant ambient temperatures, provide ample evidence of this.

Properties of Dual-Crosslinked Collagen-Based Membranes as Corneal Repair Material.

Corneal disease has become the second leading cause of blindness in the world. Corneal transplantation is currently considered to be one of the common treatments for vision loss. This paper presents a novel approach utilizing dual-crosslinked membranes composed of polyrotaxane multiple aldehydes (PRAs), 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC), and N-hydroxysuccinimide (NHS) in the development process. Collagen was crosslinked, respectively, by EDC/NHS and PRAs to form stable amide bonds and imine groups. Through the formation of a double interpenetrating network, dual-crosslinked (Col-EDC-PRA) membranes exhibited enhanced resistance to collagenase degradation and superior mechanical properties compared to membranes crosslinked with a single crosslinker. Furthermore, Col-EDC-PRA membranes display favorable light transmittance and water content characteristics. Cell experiments showed that Col-EDC-PRA membranes were noncytotoxic and were not significantly different from other membranes. In a rabbit keratoplasty model, corneal stromal repair occurred at 5 months, evidenced by the presence of stromal cells and neo-stroma, as depicted in hematoxylin-eosin-stained histologic sections and optical coherence tomography images of the anterior segment. Moreover, there was no inflammation and corneal neovascularization, as well as no corneal rejection reaction in the surgical area. Overall, the results demonstrated that the dual-crosslinked membranes served effectively for corneal tissue regeneration after corneal defect.

Light Transmission Characteristics and Cytotoxicity within A Dental Composite Color Palette.

Modern light-cured, resin-based composites are offered in a wide range of shades and translucencies. This large variation, created by varying the amount and type of pigmentation and opacifiers, is essential to enable an esthetic restoration in each patient situation, but may affect light transmission in the deeper layers during curing. We quantified optical parameters and their real-time variation during curing for a 13-shade composite palette of identical chemical composition and microstructure. Incident irradiance and real-time light transmission through 2 mm thick samples were recorded to calculate absorbance, transmittance, and the kinetic of transmitted irradiance. Data were supplemented by the characterization of cellular toxicity to human gingival fibroblasts up to 3 months. The study highlights a strong dependence of light transmission and its kinetic as a function of shade, with the largest changes occurring within the first second of exposure; the faster changes, the darker and more opaque the material. Transmission differences within progressively darker shades of a pigmentation type (hue) followed a hue-specific, non-linear relationship. Shades with similar transmittance but belonging to different hues were identified, while the corresponding kinetic was identical only up to a transmittance threshold. A slight drop in absorbance was registered with increasing wavelength. None of the shades were cytotoxic.

A Highly Transparent Flexible Antenna Based on Liquid Metal Mesh Film

In this paper, a convenient process for the fabrication of flexible liquid metal mesh films (LMMF) is proposed first. Then, the light transmittance and square resistance characteristics of LMMF are studied theoretically and experimentally. The light transmittance of the LMMF can reach 85% when the line width and spacing are 50 μm and 1000 μm, respectively. Furthermore, as an example of LMMF, a coplanar waveguide loop antenna is designed and fabricated that contains an LMMF with a line width of 50 μm and a line spacing of 500 μm. The measured square resistance and transmittance for the LMMF are 0.0456 Ω/sq and 72%, respectively. The measured peak gain of the antenna is 3.38 dBi while the average efficiency is 61%. The antenna’s working frequency covers most of the S-band, C-band, and X-band, as well as multiple channels of fifth generation (5G) communication. Therefore, the antenna can be used in fields such as radar and mobile communication. Uniquely, the fabricated antenna performs well in terms of light transmission, conductivity, and flexibility. In particular, it remains stable in stretching and bending deformation. As a highly light-transmissive stretchable flexible antenna, the antenna is equipped with various functions such as concealability, conformability, and reconfigurability. This LMMF-based antenna has good prospects for applications in the fields of flexible electronics and transparent electronics.

P2O5/ZrO2/TiO2 codoped transparent cordierite glass ceramics: Stability, crystallization and light transmittance

MgO–Al2O3–SiO2 (MAS) glass and transparent glass ceramics codoping P2O5/ZrO2/TiO2 are synthesized using conventional melt-quenching technique. Herein, the crystallization behavior of MAS parent glass, glass stability, phase composition, structure, and light transmittance characteristics of the glass ceramics are discussed. Results showed that P2O5 improved the stability of the basic glass and the obtained transparent glass ceramics crystallized via volume nucleation and one- or two-dimensional growth. In the prepared glass ceramics, α-cordierite was the predominant crystalline phase. Additionally, nanocrystals were observed in the glass ceramics. The major elements in the glass and crystalline phases were uniformly distributed based on the element distribution maps obtained via energy-dispersive X-ray spectroscopy. The resulting glass ceramics had a transmittance of >80%, indicating the feasibility of synthesizing transparent cordierite glass ceramics.

A versatile study on neuron deformation of brain through photonic structure

The neuron connections in the central nervous system play an important role in the structure of the life organ. The neurons control the operational mechanism of an entire brain which sways the intact system of the body. An itty bitty variation of neurons in the brain creates a serious complication which may lead to the brain haemorrhage. The amount of the variation/deformation of neuron in brain determines the stage of the brain stroke. So an early computation of the deformation of neuron saves from brain haemorrhage. Keeping the importance of the neuron deformation in the brain, the present article employs one dimensional photonic structure to fetch the amount of deformation in the brain using infrared (IR) signal of 1310 nm (wavelength). The principle of measurement of the deformation relies on the light transmittance characteristics of three layers of photonic structure which contains the tissues of the brain. The output power emerging from one dimensional photonic structure indicates the status of the neuron deformation. The output result infers that the amount of deformation of the of neuron decreases linearly with the increasing of an output power. Same techniques are applied for both focusing clear and CLARITY specimen for the sake of validation. For example; the outcomes of the same specify that the output power decreases from 23.9923 µW to 0.0076 µW for deformation raging from 1.0 µm to 1.4 µm of the brain from CLARITY. Similarly, the output power decreases from 29.1294 µW to 0.27956 µW for deformation raging from 1.0 µm to 1.4 µm of the brain from focus clear method. To sum up, the outcomes of the current research confirms that the amount of the deformation in the brain can be identified by knowing the output power. In short, the present work proposes a photonic crystal based sensor through which one can fetch the amount deformation of the brain by knowing the amount of transmitted signal at the output end. For example; the neuron deformation which is ranging from 1.0 µm to 1.4 µm could be known instantly by applying 1310 nm to the proposed photonic structure.

Does the thickness of universal-shade composites affect the ability to reflect the color of background dentin?

The recently introduced resin composites with a universal shade are claimed to match any tooth color. In this study, it was examined how composite thickness affects the color adjustment of conventional and universal-shade composites to background dentin. Thirty sound human central incisors of various shade were used, and color differences between their intact labial surfaces, exposed dentin surfaces and composite restorations (thickness 1-3 mm) were evaluated. In addition, the translucency, light transmission characteristics, and spectral reflectance of the composites were measured. The results showed that universal-shade composites outperformed conventional composites of A2 shade in the adjustment of hue and chroma (p<0.05) but not in lightness (p>0.05). The color adjustment potential of all composites significantly decreased as their thickness increased (p<0.05). The effect of thickness on Omnichroma and Omnichroma Flow was less marked, presumably because of their higher translucency (p<0.05) and structural coloration which induces light reflectance in the yellow-to-red range.

Polarized light transmission characteristics in a smoky ellipsoidal particle medium.

True natural environments are more complex, and light travels through non-spherical particle media, which can affect the transmission of light. The medium environment of non-spherical particles is more common than that of spherical particles, and some studies have shown that there are differences between spherical and non-spherical particles in polarized light transmission. Therefore, the use of spherical particles instead of non-spherical particles will result in great error. In view of this feature, this paper samples the scattering angle based on the Monte Carlo method, and then constructs a simulation model of a random sampling fitting phase function suitable for ellipsoidal particles. In this study, yeast spheroids and Ganoderma lucidum spores were prepared. The effects of different polarization states and optical thicknesses on the transmission of polarized light at three wavelengths were investigated using ellipsoidal particles with a ratio of 1.5 transverse to vertical axes. The results show that when the concentration of the medium environment increases, the polarized lights of different states all show obvious depolarization, but circularly polarized light has better polarization-preserving characteristics than linearly polarized light, and polarized light with larger wavelengths also shows more stable optical properties. When yeast and Ganoderma lucidum spores were used as the transport medium, the degree of polarization of polarized light had the same trend. However, the equal volume radius of yeast particles is smaller than that of Ganoderma lucidum spores, so when the laser is in the yeast particle medium, the polarization-maintaining property of polarized light is superior. This study provides an effective reference for the variation of polarized light transmission in an atmospheric transmission environment with heavy smoke.

Effect of atmospheric turbulent on mobile ultraviolet wireless communications

This paper proposes a method to study the transmission characteristics of ultraviolet turbulent channels, by considering the variation of atmospheric refractive index structure parameters along transmission paths. This method is adopted in a Monte Carlo simulation to analyze the transmission characteristics of ultraviolet light when the communication nodes are mobile. The analysis focuses on the influence of the moving speed and direction of the receiver on path loss under long-distance and atmospheric turbulence conditions. The simulation results show that, when the altitude increases, atmospheric refractive index structure parameters show a decreasing trend, and the path loss of the system decreases. With or without turbulence, when the receiver moves away from the transmitter in a horizontal plane, the received signal strength always decreases as the moving speed increases; and vice versa. When the receiver moves along the vertical axis, the signal strength increases as the moving speed increases. With the presence of atmospheric turbulence, the received signal strength attenuates significantly, compared with the case with no turbulence. When the receiver moves along the vertical axis, the path loss is higher compared with the situation when the receiver moves on the horizontal plane.

Research and Application of Multi-Mode Joint Monitoring System for Shaft Wall Deformation.

The mine shaft is an important channel linking the underground with the surface, undertaking important functions such as personnel and material transportation and ventilation. Thus the shaft, known as the throat of the mine, is the production hub of the whole mine. Since 1980, damage to coal mine shafts has occurred in many areas of China, which has seriously impacted the safety of mine production. Therefore, real-time monitoring of the shaft wall condition is necessary. However, the traditional monitoring method cannot achieve long-term, continuous and stable monitoring of the shaft wall due to the harsh production environment downhole. Hence, a multi-mode joint sensing system for shaft wall deformation and damage is proposed, which is mainly based on FBG sensing and supplemented by vibrating-string sensing. The principle of FBG sensing is that when the external environment such as temperature, pressure and strain changes, the characteristics of light transmission in the FBG such as wavelength, phase and amplitude will also change accordingly. Using the linear relationship between the strain and the wavelength shift of the FBG, the strain of the measured structure is obtained by calculation. Firstly, this paper introduces the basic situations of the mine and analyzes the causes shaft damage. Then the vertical and circumferential theoretical values at different shaft depths are derived in combination with the corresponding force characteristics. Moreover, a four-layer strain transfer structure model of the shaft consisting of the fiber, the protective layer, the bonding layer and the borehole wall is established, which leads to the derivation of the strain transfer relational expression for the surface-mounted FBG sensing on the shaft wall. The strain-sensing transfer law and the factors influencing the strain-sensing transfer of the surface-mounted FBG on the shaft wall are analyzed. The order of key factors influencing the strain-sensing transfer is obtained by numerical simulation: the radius of the protective layer, the length of the FBG paste, and the elastic modulus of the adhesive layer. The packaging parameters with the best strain-sensing transfer of the surface-mounted FBG on the shaft wall are determined. A total of six horizontal level monitoring stations are arranged in a coal mine auxiliary shaft. Through the comprehensive analysis of the sensing data of the two sensors, the results show that the average shaft wall strain–transfer efficiency measured by the FBG sensor reaches 94.02%. The relative average error with the theoretical derivation of shaft wall transfer efficiency (98.6%) is 4.65%, which verifies the strain transfer effect of the surface-mounted FBG applied to the shaft wall. The shaft wall’s deformation monitoring system with FBG sensing as the main and vibrating-string sensing as the supplement is important to realize the early warning of well-wall deformation and further research of the shaft wall rupture mechanism.

Role of Magnetic Nanoparticles Size and Concentration on Structural Changes and Corresponding Magneto-Optical Behavior of Nematic Liquid Crystals.

The effect of magnetic nanoparticles size and concentration on nematic liquid crystal (NLC) behavior in a magnetic field was investigated. The magneto-optical investigation using measurements of the light transmission through the liquid crystal was used to study the structural changes induced by an applied weak magnetic field. Magnetic nanoparticles Fe3O4 of spherical shape with different size and volume concentration were added to NLC 4-cyano-40 -hexylbiphenyl (6CB) during its isotropic phase. In contrast to undoped liquid crystals, the distinctive different light transmission responses induced by a magnetic field in studied NLC samples were observed suggesting both structural changes and the orientational coupling between magnetic moments of nanoparticles and the director of the NLC. Experimental measurements were conducted, including investigation under linearly increasing and/or jumped magnetic field, respectively, as well as the investigation of time influence on structural changes to study their stability and switching time. The analysis of observed light transmission characteristics confirmed the role of concentration and size of magnetic nanoparticles on the resultant behavior of investigated NLC compounds. The obtained results showed the lowering of the threshold magnetic field with an increase in the volume concentration of nanoparticles and on the important role of nanoparticles size on stability and switching properties. Obtained results are discussed within the context of previous ones.