Variation Of Transmittance Research Articles

Tail Artifact Removal via Transmittance Effect Subtraction in Optical Coherence Tail Artifact Images

Optical Coherence Tomography Angiography (OCTA) has revolutionized non-invasive, high-resolution imaging of blood vessels. However, the challenge of tail artifacts in OCTA images persists. In response, we present the Tail Artifact Removal via Transmittance Effect Subtraction (TAR-TES) algorithm that effectively mitigates these artifacts. Through a simple physics-based model, the TAR-TES accounts for variations in transmittance within the shallow layers with the vasculature, resulting in the removal of tail artifacts in deeper layers after the vessel. Comparative evaluations with alternative correction methods demonstrate that TAR-TES excels in eliminating these artifacts while preserving the essential integrity of vasculature images. Crucially, the success of the TAR-TES is closely linked to the precise adjustment of a weight constant, underlining the significance of individual dataset parameter optimization. In conclusion, TAR-TES emerges as a powerful tool for enhancing OCTA image quality and reliability in both clinical and research settings, promising to reshape the way we visualize and analyze intricate vascular networks within biological tissues. Further validation across diverse datasets is essential to unlock the full potential of this physics-based solution.

Electrochemical Copolymerization of Poly (MET-EDOT) with Enhanced Cyclic Stability

To enlarge the electrochromic cyclic lifetime of poly (3-methtylthiophene) (PMET), the EDOT was copolymerized with the P3MT by electrochemical polymerization. The constant potential of 2.2 V was applied to the copolymer film growth in the electrolyte with 0.001 M EDOT and 0.1 M MET. The copolymer was achieved through the characteristics of the FT-IR and Raman analysis. The PMET-EDOT retained the vivid EC color from the PMET and the long cyclic stability from the PEDOT. The transmittance contrast of PMET-EDOT only decayed 1.5% after 1000 cycles. During the few components of EDOT in the copolymer, it seems similar that the transmittance spectrum and variation between the PMET-EDOT and PMET.

Effects of Heat Treatment on the Microstructure and Optical Properties of Sputtered GeO2 Thin Films

Microstructure and composition significantly influence the physical properties of thin films. Therefore, these can be adapted to enhance the functionality of thin films for practical applications. Herein, the anomalous microstructural evolution of sputtered GeO2 thin films based on postdepositional heat treatments is reported. Temperature‐dependent microstructural variations are investigated systematically via a combinatorial postdepositional heat treatment employing a natural thermal gradient in a tube furnace. Heat treatment under an oxidizing atmosphere results in a transition from the amorphous phase to the quartz phase, and subsequent heat treatments under a reducing atmosphere cause H2O‐incorporated chemical reactions. Hence, these conditions create unique microstructural features and yield optical transmittance variations in the GeO2 thin films. The phase transition induces the formation of spherulitic hexagonal GeO2 crystallites, and further increase in the temperature promotes the agglomeration of crystallites in the amorphous matrix. The incorporation of H2O results in the growth of the microstructure, and the chemical reduction to Ge metal begins to generate small granules from the boundary of the microstructures. The experimental results and proposed mechanisms presented herein for the microstructural and compositional changes serve as references for designing the physical properties of thin films.

Large-range and high-sensitivity displacement sensing based on a SNAP microresonator by multimode encoding technique

Probe-type micro-displacement sensors with a large range and high sensitivity have important applications in both aerospace and nano-lithography. However, the state-of-the-art measurement range achieved using conventional methods such as charge coupled device imaging and fiber grating demodulation is limited to only tens of micrometers. In this study, we propose and demonstrate a displacement sensing mechanism with a large range and high sensitivity for measuring linear displacements. The mechanism is based on a multimode encoding technique implemented on a surface nanoscale axial photonics (SNAP) microcavity platform. By tracking the transmittance variations of multiple axial modes and employing encoding techniques, we can determine the rough absolute position as well as the axial mode with the highest sensitivity in each region. Moreover, the selected mode for each region is exploited to accurately measure the micro-displacement with a large range and high accuracy. As a proof-of-principle experiment, the results indicate a large sensing range about 346 μm and a high sensitivity ranging up to 0.013 μm−1. Assuming that the transmittance can be resolved by 0.1%, the resolution of the measurement is about 0.1 μm.

P‐36: The impact of packaging film on the uniformity of mini LED display

The impact of packaging film has been discussed for the uniformity of mini LED screen. It is found that the variation of transmittance of the packaging film should be controlled in a limited range which is about 5% to ensure the uniformity of mini LED display at side viewing angle.

Spatio-Temporal Dynamics of Diffusion-Associated Deformations of Biological Tissues and Polyacrylamide Gels Observed with Optical Coherence Elastography.

In this work, we use the method of optical coherence elastography (OCE) to enable quantitative, spatially resolved visualization of diffusion-associated deformations in the areas of maximum concentration gradients during diffusion of hyperosmotic substances in cartilaginous tissue and polyacrylamide gels. At high concentration gradients, alternating sign, near-surface deformations in porous moisture-saturated materials are observed in the first minutes of diffusion. For cartilage, the kinetics of osmotic deformations visualized by OCE, as well as the optical transmittance variations caused by the diffusion, were comparatively analyzed for several substances that are often used as optical clearing agents, i.e., glycerol, polypropylene, PEG-400 and iohexol, for which the effective diffusion coefficients were found to be 7.4 ± 1.8, 5.0 ± 0.8, 4.4 ± 0.8 and 4.6 ± 0.9 × 10-6 cm2/s, respectively. For the osmotically induced shrinkage amplitude, the influence of the organic alcohol concentration appears to be more significant than the influence of its molecular weight. The rate and amplitude of osmotically induced shrinkage and dilatation in polyacrylamide gels is found to clearly depend on the degree of their crosslinking. The obtained results show that observation of osmotic strains with the developed OCE technique can be applied for structural characterization of a wide range of porous materials, including biopolymers. In addition, it may be promising for revealing alterations in the diffusivity/permeability of biological tissues that are potentially associated with various diseases.

High-Performance On-Chip Racetrack Resonator Based on GSST-Slot for In-Memory Computing.

The data shuttling between computing and memory dominates the power consumption and time delay in electronic computing systems due to the bottleneck of the von Neumann architecture. To increase computational efficiency and reduce power consumption, photonic in-memory computing architecture based on phase change material (PCM) is attracting increasing attention. However, the extinction ratio and insertion loss of the PCM-based photonic computing unit are imperative to be improved before its application in a large-scale optical computing network. Here, we propose a 1 × 2 racetrack resonator based on Ge2Sb2Se4Te1 (GSST)-slot for in-memory computing. It demonstrates high extinction ratios of 30.22 dB and 29.64 dB at the through port and drop port, respectively. The insertion loss is as low as around 0.16 dB at the drop port in the amorphous state and about 0.93 dB at the through port in the crystalline state. A high extinction ratio means a wider range of transmittance variation, resulting in more multilevel levels. During the transition between crystalline and amorphous states, the tuning range of the resonant wavelength is as high as 7.13 nm, which plays an important role in the realization of reconfigurable photonic integrated circuits. The proposed phase-change cell demonstrates scalar multiplication operations with high accuracy and energy efficiency due to a higher extinction ratio and lower insertion loss compared with other traditional optical computing devices. The recognition accuracy on the MNIST dataset is as high as 94.6% in the photonic neuromorphic network. The computational energy efficiency can reach 28 TOPS/W, and the computational density of 600 TOPS/mm2. The superior performance is ascribed to the enhanced interaction between light and matter by filling the slot with GSST. Such a device enables an effective approach to power-efficient in-memory computing.

Phase selectivity of ternary Zn-O-Sn films regulated by oxygen and fluorine

The evolvement of ternary Zn-O-Sn systems were selected through oxygen-controlled sputtering and oxygen-subtracted annealing as well as introduction of fluorine. Through XRD, Raman, PL, AFM, Transmittance, Hall-effect Testing and Resistance variation on sensing H2, the selection and formation mechanism of optional phases in the ternary Zn-O-Sn systems were clarified. During the sputtering process, oxygen addition could contribute to the selected growth of dual-phase Zn2SnO4/SnO2 with an aerobic characteristic. On the contrary, either oxygen subtraction or fluorine introduction was beneficial to the preferred growth of amorphous ZnSnO3 with an anaerobic characteristic which could further crystallize to single-phase perovskite ZnSnO3 following the vacuum annealing. Compared with dual-phase Zn2SnO4/SnO2 deposited under oxygen-containing ambience, single-phase amorphous ZnSnO3 with more oxygen vacancies presented a less light-scattered transmittance with the flattened absorption edge, a high carrier concentration ∼1017 cm−3 as well as a low carrier mobility ∼100 cm2/V·s, and a rapid response/recover rate of resistance on sensing H2.

Nanoparticulate films of WO3 and MoO3 composites for enhancing UV light electrochromic transmittance variation and energy storage applications

Green technologies for the manufacture of optical shutters retain a sustainable development. In this work, the electro-exploding wires and spray coating technologies are employed to deposit nanoparticulate (WO3)1-x(MoO3)x composite films. MoO3 NPs are introduced to enhance electrochromic (EC) transmittance variation of violet and UV light with wavelengths ranging from 330 to 450 nm. Measurements of EC performances of (WO3)1-x(MoO3)x composite films in a potentiostat are carried out to discern beneficial from MoO3 addition. It is observed that the diffusion coefficient and the charge density increase with an increment of MoO3 concentration. The coloration efficiency at 430 nm raises apparently whereas that at 633 nm does not show a significant variation with increasing MoO3 concentrations. In addition, the EC device with ∼12.5% of MoO3 introduced reveals a much higher optical modulation at 430 nm. From the measurements of galvanostatic charge-discharge curves of EC films in the potentiostat, the areal capacitances of 12.9 and 14.0 mF/cm2 are estimated for pure and ∼12.5% MoO3 introduced WO3 EC films. The EC batteries are demonstrated and the enlarged energy storage capability with an addition of MoO3 is observed. The simple introduction of MoO3 into WO3 nanoparticulate films compensates drawbacks of WO3 films and enhances EC performances and energy storage capabilities.

The Effect of Transparent Conducting Oxide Films on WO3-Based Electrochromic Devices with Conducting Polymer Electrolytes

Over the past few decades, electrochromism has been a prominent topic in energy-saving applications, which is based on the mechanism of altering the optical transmittance of EC materials under the effect of a small applied voltage. Thus, tungsten oxide (WO3) is a significant chemical compound typically applied in electrochromic devices (ECDs) as it is responsible for the optical transmittance variation. In this work, the WO3 films were produced through a sol-gel spin-coating method. The effect of various transparent conducting oxides (TCOs, which are indium-doped tin oxide (ITO), fluorine-doped tin oxide (FTO) glass substrates, and aluminum-doped zinc oxide (AZO)) was investigated in the construction of ECDs. Based on a conducting polymer polypyrene carbonate electrolyte, ITO and aluminum-doped zinc oxide (AZO)-coated glasses were also examined as counter electrodes. The electrode combination employing FTO and ITO as the TCO and counter electrode, respectively, exhibited the most significant coloration efficiency of 72.53 cm2/C. It had coloring and bleaching transmittance of 14% and 56%, respectively, with a large optical modulation of 42%. In addition to that, ECDs with the AZO counter electrode have the advantage of lower intercalation charges compared to ITO and FTO. Hence, this research offers a new avenue for understanding the role of common TCO and counter electrodes in the development of WO3-based ECDs with conducting polymer electrolytes.

CAMBIOS EN LA TRANSMITENCIA DEL ELECTROLITO A 254nm SEGÚN EL ESTADO DE SALUD DE LAS BATERÍAS DE PLOMO

The estimation of the state of health (SOH) of lead-acid batteries for electrical energy storage is an important factor when planning their replacement and energy management. There are many methods to calculate this parameter. The novelty of this work is that it employs an optical method that produces compelling results showing the variation of the UVC transmittance of the electrolyte when the battery has different SOH levels, which is a novel alternative to the existing one of ampere counting, which is also experimented within this work.

A novel Pt loading method for WO3 gasochromic film and the morphology control of the film by two-step solvothermal synthesis

Controlling the morphology and structure of nanofilms is an important way to improve their properties. Herein, we report a two-step solvothermal method for preparing nanostructured WO3 film composed of single crystal WO3 nanowires, by which much more flexible morphology control than the traditional one-step method is realized. The film prepared by this method combines the morphological characteristics of two one-step films by changing the solution composition during each step. To obtain gasochromic film, a novel method named “charging-immersing” method is used to load catalyst Pt on the WO3 film. In this novel method, WO3 film is first charged and then immersed in the K2PtCl4 solution, reducing Pt nanoparticles from solution. The variation of transmittance, coloring rate (in 4% H2/Ar) and bleaching rate (in the air) of the film synthesized by two-step method at the wavelength of 1000 nm are 76.2%, 4.57%/s and 1.29%/s, respectively. While the properties of two one step films are 69.2% and 40.9%, 2.73%/s and 1.72%/s, 0.063%/s and 1.42%/s, respectively. The combination of morphology leads to the combination of performance advantages because new morphology (thin WO3 nanowires and relatively large Pt nanoparticles) is more conducive to the dissociation of H2 and diffusion of H and O atoms during gasochromism. This study offers a novel strategy for morphology control of nanostructured WO3 film prepared by solvothermal method and loading catalyst Pt on it.

Laser Protection Properties of Multi-Band Non-Regularized Highly Reflective Films

With the increasing exploitation of lasers, single-band laser protection has been extensively studied. However, single-band laser protection techniques have remained expensive and failed to meet protection requirements for multi-band lasers. In addition, the actual use of protective films requires a specific transmittance, which is generally not met by regular films. Here, we deposited three non-regularized highly reflective films using SiO2 as the low-refractive-index material and TiO2, HfO2, and Ta2O5 as the high-refractive-index materials by thermal evaporation for achieving multi-band laser protection. To verify the effectiveness of the films, the variation in transmittance, damage threshold, standing-wave electric field, and damage morphology of the films were analyzed at two laser wavelengths, and their protection mechanisms were evaluated based on optical properties and damage resistance. The results showed that the reflectances of the prepared non-regularized films at 1064 nm and 532 nm were greater than 99%, and the laser-induced damage thresholds for TiO2/SiO2, HfO2/SiO2, and Ta2O5/SiO2 films were 5.99, 5.89, and 9.99 J/cm2 at 1064 nm and 3.04 J/cm2, 1.48 J/cm2, and 4.93 J/cm2 at 532 nm, respectively, demonstrating good laser protection. The present work provides a practical and effective solution for multi-band laser protection and the prepared films may be used in numerous laser applications.

High sensitivity photonic crystal sensor based on transition between photonic bands

In this work, we performed a study of an interferometric high sensitivity photonic crystal (PhC) sensor applied to measure glucose concentration in human urine samples. The architecture of the photonic sensor numerically simulated is based on a Mach–Zehnder interferometer formed by a coupled waveguide-cavity system. The sensor operates using photonic mode transitions detected from the photonic band diagram analysis, driven by changes in the glucose concentration in the urine samples that affect the refractive index of the optical sampling cavity. The photonic mode transition causes a phase shift between the wave traveling in the reference arm of the interferometer and the propagating electromagnetic wave in the sensing cavity containing the probing sample. As a consequence, the transmittance at the output of the interferometer can be modulated, making it extremely sensitive to changes in the refractive index of the sensing cavity. Since the PhC sensor studied works under variations in transmittance, we proposed a sensitivity coefficient as a function of the change in transmittance per unit change in the refractive index. The sensitivity achieved by the photonic sensor presents a value of 7000%/RIU, which indicates a variation in transmittance of 70% for changes in the refractive index of 0.01. These results demonstrate the feasibility of using photonic transitions between modes as a sensing tool in integrated photonic devices.

Tuning the main electrochromic features by polymer backbone variation of triphenylamine-based polyamides

A novel triphenylamine (TPA)-based diamine integrating structural elements to endow highly stable redox and electrochromic features was successfully synthesized and structurally characterized. Three new TPA-containing polyamides were obtained via polycondensation of this diamine with acid dichlorides, as confirmed by thorough NMR and FT–IR investigations. The main electronic transitions and specific oxidation sites were evaluated by photo-optical and (time-dependent) density functional theory ((TD)– DFT) analysis, respectively. Cyclic voltammetry and spectroelectrochemical investigations were used to assess the redox stability and to comprehend the electrochromic conduct in terms of electrochromic contrast, response time, and switching stability. Thus, the synthesized polyamides integrated high transmittance variation up to 67%, response time to coloring and blanching down to 6.52 s/2.01 s, a maximum of 219 cm2/C of the electrochromic efficiency (EC) and a decay up to 5% after 500 cycles. All these electrochromic parameters and their variation are contingent to the electronic effect of each acid dichloride segment from the polymers. Also, the presence of the ortho-catenated methyl groups lowered the overall oxidation potentials and therefore triggered long-term stability. Computational evaluations were used to endorse practical assessments. All experimental and theoretical observations were subjected to interconnected reasoning to determine the correlations between structural motifs and resulting electrochromic performances.

Applied IrO2 Buffer Layer as a Great Promoter on Ti-Doping V2O5 Electrode to Enhance Electrochromic Device Properties.

Electrochromic devices (ECDs) are a promising material for smart windows that are capable of transmittance variation. However, ECDs are still too expensive to achieve a wide market reach. Reducing fabrication cost remains a challenge. In this study, we inserted an IrO2 buffer layer on Ti-doped V2O5 (Ti:V2O5) as a counter electrode using various Ar/O2 gas flow ratios (1/2, 1/2.5, 1/3 and 1/3.5) in the fabrication process. The buffered-ECD resulted in a larger cyclic voltammetry (CV) area and the best surface average roughness (Ra = 3.91 nm) to promote electrochromic performance. It was fabricated using the low-cost, fast deposition process of vacuum cathodic arc plasma (CAP). This study investigates the influence of the IrO2 buffer/Ti:V2O5 electrode on ECD electrochemical and optical properties, in terms of color efficiency (CE) and cycle durability. The buffered ECD (glass/ITO/WO3/liquid electrolyte/IrO2 buffer/Ti:V2O5/ITO/glass) demonstrated excellent optical transmittance modulation; ∆T = 57% (from Tbleaching (67%) to Tcoloring (10%)) at 633 nm, which was higher than without the buffer (ITO/WO3/liquid electrolyte/Ti:V2O5/ITO) (∆T = 36%). In addition, by means of an IrO2 buffer, the ECD exhibited high coloration efficiency of 96.1 cm2/mC and good durability, which decayed by only 2% after 1000 cycles.

Structure and electrochemical property of single-crystal α-MoO3 microbelts synthesized by a solid-state reaction

In this paper, we report the simple and cost-effective synthesis of α-MoO3 microbelts with side lengths on the centimeter or millimeter scale by one-step sintering using MoO3 powder. Transparent and flat microbelts revealing (0k0) plane facets cleaved preferentially along the [001] direction are formed without the use of supporting substances in air. Atomic force microscopy and high-resolution transmission electron microscopy analyses confirm that a single-crystal microbelt composed of stacked bunches of α-MoO3 sheets is synthesized. The effect of the synthesis conditions on the structure and size of the α-MoO3 microbelts is systematically investigated by varying the residual time during sintering and the amount of the source powder. Finally, we demonstrate the electrochemical properties of the single-crystal α-MoO3 microbelt in an acidic solution; the microbelt exhibits a variation in transmittance with the application of a potential, implying that it is electrochromic and possesses ion-storage capacity, making it promising for application in supercapacitors. Our study proposes a novel and facile method for the large-scale preparation of α-MoO3 microbelts, which will open up new avenues in the field of electrochemical devices.

Effect of different annealing conditions on CdZnTe thin films for absorber layer applications

The Silicon based single junction and perovskite solar cells have demonstrated high efficiency but Silicon based cells suffer from the drawback of higher cost and perovskite solar cells are not stable and degradable in environment. The thin film based CIGS and CdTe cells have achieved efficiency of more than 22% but, particularly, the CdTe thin film solar cells require a suitable back contact which can be obtained by doping of Zn element in CdTe. The grain growth in CdTe-based films is attained by chloride treatment and therefore, in order to seek applicability of chloride treatment on CdZnTe (CZT) thin films, the present communication reports an evolution of different annealing conditions (in air, CdCl2 and MgCl2 environments) on physical properties to electron beam evaporated CdZnTe thin films. The XRD diffractograms revealed to the dominance of cubic phased peak corresponding to (111) plane and augmentation in grain size with treatment temperature. The optical spectra indicated variation in absorbance and transmittance with temperature of treatments and Tauc's plots demonstrated band gap of all the films in 1.41–1.55 eV range. Current-voltage characteristics divulged Ohmic character of films where conductivity and resistivity are eventually modified with annealing conditions. The FESEM micrographs of pristine films represented bouncy grains with some vacant spaces whereas chloride treated films showed larger grains. The EDS patterns confirmed the deposition of CdZnTe thin films and treatments concerned. The AFM maps demonstrated deep valley-like and hill-like configurations of processed films. The obtained results signify that the films annealed at 300 °C aver their suitability for absorber layer roles in development of efficient solar cells with single junction and tandem architectures.

Temperature-controlled spectrophotometry: a simultaneous analysis of phase transition, thermal degradation and optical properties of semi-transparent composites from 20 °C to 450 °C.

So far, optical and effective radiative properties of polymer matrix based composites were investigated at temperatures well below their degradation temperature. At the same time, polymers exhibit temperature dependent physical properties and may undergo structural changes as their temperature raises. In this work, we employ the "Temperature-Controlled Spectrophotometry", a new method enabling to identify simultaneously phase transitions, thermal degradation and radiative properties of semi-transparent composites over a large temperature range. The method consists of measuring simultaneously the normal-normal and the normal-hemispherical transmittances and reflectances of the sample subjected to a laser irradiation with tuneable wavelength while the temperature is rised from room temperature up to 450 °C by means of a CO2 laser. Physical changes of the sample are identified from the temperature variation of normal-normal transmittance and specular reflectance measurements. Most of the results here are presented at a specific wavelength of 1070 nm but the proposed method is suitable over the semi-transparency spectral domain of the material by changing the wavelength of the probe laser. An inverse method for parameter identification based on normal-hemispherical measurements is employed to determine the transport effective radiative properties of the sample, namely the transport extinction coefficient and the transport scattering albedo from room temperature to 325 °C.

Design of Moiré-Inspired Metasurface Lens for Focusing Electromagnetic Power in Fresnel Near-Field Region

This paper proposes a Moiré-inspired metasurface lens system to focus electromagnetic power in the Fresnel near-field region. The proposed metasurface lens (MSL) system is composed of two MSLs and a square patch antenna source. The MSLs are modeled based on the transmit phase distributions of Moiré lens theory, and each unit cell structure (patch shape and Jerusalem cross slot shape) is determined to fit the calculated transmit phase distributions at each location. When changing the unit cell structure, phase and transmittance variations are achieved over 330° and −3 dB. The square patch antenna source is then designed to excite the field to the MSLs. The measured reflection coefficients are below −10 dB at 5.8 GHz while rotating the second MSL. The focal length can be adjusted from a minimum of 38 cm to a maximum of 110 cm according to the rotation angle of the second MSL. The proposed MSL system can be employed for wireless power transmission applications to focus electromagnetic power at various locations in the near-field region.