Measurements Of Optical Properties Research Articles

Evaluation of Optical Characteristic of Animal Fat using Au Nanoparticle in Bamboo-derived Nanocellulose Paper Substrate: A Comparative Study

Detection of animal fat content is necessary to prevent inappropriate product composition labelling measures such as substituting beef with pork or adding lard to other fat-processed products. In this paper, a detection method of animal fat utilizing paper-based biosensors using nano cellulose paper substrate is proposed. The nanocellulose paper substrate was fabricated using bamboo fibre and parenchyma cells. The nanocellulose paper substrate was further decorated with Au nanoparticles to improve the detection’s sensitivity. It demonstrated the measurement of optical properties using UV-vis spectroscopy for several animal fats. It also presented a colorimetric detection using a light source, photodetector, and imaging analysis. It was shown the difference in the color space intensity value before and after the addition of lard samples on AuNP-modified nanocellulose paper. It was reported that the difference in grayscale intensity value of AuNP-modified nanocellulose paper with a reducing agent volume of 3 mL and 4 mL were 37.369 and 55.686, respectively. This demonstrated that the larger the volume of reducing agent added during synthesis, the smaller the size of the nanoparticles and increasing the sensitivity of the sensor. The proposed paper-based biosensor offered a simple fabrication, biodegradable, and can be implemented in a colorimetric imaging system.

ZnSb Films on Flexible Substrates: Stability, Optical Bandgap, Electrical Properties, and Indium Doping

AbstractUndoped and In‐doped ZnSb thin films are deposited on rigid glass and flexible polyimide (Kapton) by physical vapor deposition. Detailed structural and chemical characterization is performed along with measurement of electrical and optical properties. These properties are very similar for films on glass and Kapton. Flexible ZnSb films show remarkable stability of electrical and optical properties, which are unchanged after 104 cycles of linear bending with surface strain 0.18%. Only severe flexing after this treatment (torsional bending with surface strain 1.7%) causes progressive degradation of conductivity over tens to hundreds of cycles. The ZnSb optical direct gap is determined to be 0.89 ± 0.05 eV. The optical direct gap of β Zn4Sb3 was 1.07 ± 0.05 eV. Other absorption features in the films, including smaller indirect gaps, are discussed.

AGe2O4Q (A = Ba, Sr; Q = S, Se): A series of heteroanionic oxychalcogenides with large birefringence

Heteroanionic materials are of current research interest owing to their varied structural chemistry and properties. Recently, a number of heteroanionic materials have been synthesized that can be used for water splitting, battery materials, thermoelectrics, and nonlinear optical applications. Birefringent heteroanionic materials are still rarely researched. Herein, we report a series of new oxychalcogenides, AGe2O4Q (A = Ba, Sr; Q = S, Se), that are synthesized by solid-state reactions in fused silica tubes with their structures determined by single-crystal X-ray diffraction. Optical property measurements show that AGe2O4Q (A = Ba, Sr; Q = S, Se) exhibit large birefringences, 0.13–0.19 @ 1064 nm. These are one-order of magnitude larger than their single-anionic homologue, BaGe2O5 - 0.03 @ 1064 nm. This suggests that constructing heteroanions through using chalcogenides to partially substitute O in tetrahedral foundation building units (FBUs) is a viable method for designing new birefringent materials. Furthermore, the crystal structures, UV–vis–NIR diffuse reflectance spectra, infrared and Raman spectra as well as the first-principles calculations for AGe2O4Q (A = Ba, Sr; Q = S, Se) are also reported.

An Open‐Source Multifunctional Testing Platform for Optical Phase Change Materials

Owing to their unique tunable optical properties, chalcogenide phase change materials are increasingly being investigated for optics and photonics applications. However, in situ characterization of their phase transition characteristics is a capability that remains inaccessible to many researchers. Herein, a multifunctional silicon microheater platform capable of in situ measurement of structural, kinetic, optical, and thermal properties of these materials is introduced. The platform can be fabricated leveraging industry‐standard silicon foundry manufacturing processes. This platform is fully open‐sourced, including complete hardware design and associated software codes.

Precious metal clusters as fundamental agents in bioimaging usability.

Fluorescent nanomaterials (NMs) are widely used in imaging techniques in biomedical research. Especially in bioimaging systems, with the rapid development of imaging nanotechnology, precious metal clusters such as Au, Ag, and Cu NMs have emerged with different functional agents for biomedical applications. Compared with traditional fluorescent molecules, precious metal clusters have the advantages of high optical stability, easy regulation of shape and size, and multifunctionalization. In addition, NMs possess strong photoluminescent properties with good photostability, high release rate, and sub-nanometer size. They could be treated as fundamental agents in bioimaging usability. This review summarizes the recent advances in bioimaging utilization, it conveys that metal clusters refer to Au, Ag, and Cu fluorescent clusters and could provide a generalized overview of their full applications. It includes optical property measurement, precious metal clusters in bioimaging systems, and a rare earth element-doped heterogeneous structure illustrated in biomedical imaging with specific examples, that provide new and innovative ideas for fluorescent NMs in the field of bioimaging usability.

Quantitative hemodynamic imaging: a method to correct the effects of optical properties on laser speckle imaging.

Studying cerebral hemodynamics may provide diagnostic information on neurological conditions. Wide-field imaging techniques, such as laser speckle imaging (LSI) and optical intrinsic signal imaging, are commonly used to study cerebral hemodynamics. However, they often do not account appropriately for the optical properties of the brain that can vary among subjects and even during a single measurement. Here, we describe the combination of LSI and spatial-frequency domain imaging (SFDI) into a wide-field quantitative hemodynamic imaging (QHI) system that can correct the effects of optical properties on LSI measurements to achieve a quantitative measurement of cerebral blood flow (CBF). We describe the design, fabrication, and testing of QHI. The QHI hardware combines LSI and SFDI with spatial and temporal synchronization. We characterized system sensitivity, accuracy, and precision with tissue-mimicking phantoms. With SFDI optical property measurements, we describe a method derived from dynamic light scattering to obtain absolute CBF values from LSI and SFDI measurements. We illustrate the potential benefits of absolute CBF measurements in resting-state and dynamic experiments. QHI achieved a 50-Hz raw acquisition frame rate with a field of view and flow sensitivity up to . The extracted SFDI optical properties agreed well with a commercial system (). The system showed high stability with low coefficients of variations over multiple sessions within the same day () and over multiple days (). When optical properties were considered, the in-vivo hypercapnia gas challenge showed a slight difference in CBF ( to 0.5% difference). The in-vivo resting-state experiment showed a change in CBF ranking for nine out of 13 animals when the correction method was applied to LSI CBF measurements. We developed a wide-field QHI system to account for the confounding effects of optical properties on CBF LSI measurements using the information obtained from SFDI.

Dielectric and optical properties, high temperature conduction, and relaxation behavior of donor-element modified NBST material

The relaxor ferroelectrics (Na0.33Bi0.33Sr0.33) (Ti1-xW0.666x)O3, where 0%≤ x ≤7% (NBST+0W, NBST+3W, NBST+5W, and NBST+7W), were prepared using the solid-state reaction method. X-ray diffraction analysis showed that perovskite structures were formed at room temperature. Microstructural characterization, as well as optical and dielectric property measurements, yielded the following results: substituting Ti4+ with the donor element W6+ led to a decrease in the average grain size, dielectric loss, degree of diffusivity, and affected the temperature Tm. In the case of x = 3% of WO3, the electrical conductivity of NBST improved at high temperatures. However, the compound (NBST+7W) exhibited a low optical gap energy and high electrical conductivity at room temperature. The electrical conductivity curves were fitted by Jonscher power law, which showed that the correlated barrier hopping (CBH) model was the most dominant. Comparison of the imaginary part of impedance and electric modulus revealed that the relaxation of charge carriers in the basic compound NBST+0W occurred at both long and short ranges. However, after doping, the relaxation occurred only at a short range.

Photopyroelectric technique for the measurement of optical properties of pure liquids

Photopyroelectric technique, in the transmission configuration, was shown adequate for the measurement of the optical properties of pure liquids. The analytical scheme involves the scanning of the photopyroelectric signal as a function of the sample thickness. Optical absorption coefficients, at four wavelengths in the near infrared region (904 nm, 980 nm, 1310 nm, and 1550 nm), were measured for eight pure substances, distilled water and glycerol, among them. Strong optical absorption was obtained, particularly for pure liquids with a hydroxyl group in their molecular structure. In order to figure out about the influence of this chemical group on optical properties as function of the size of the molecule, optical absorption coefficient for a series of linear alcohols at 1550 nm was also measured.

Impact of Atmospheric Correction on Classification and Quantification of Seagrass Density from WorldView-2 Imagery.

Mapping the seagrass distribution and density in the underwater landscape can improve global Blue Carbon estimates. However, atmospheric absorption and scattering introduce errors in space-based sensors' retrieval of sea surface reflectance, affecting seagrass presence, density, and above-ground carbon () estimates. This study assessed atmospheric correction's impact on mapping seagrass using WorldView-2 satellite imagery from Saint Joseph Bay, Saint George Sound, and Keaton Beach in Florida, USA. Coincident in situ measurements of water-leaving radiance (), optical properties, and seagrass leaf area index (LAI) were collected. Seagrass classification and the retrieval of LAI were compared after empirical line height (ELH) and dark-object subtraction (DOS) methods were used for atmospheric correction. DOS left residual brightness in the blue and green bands but had minimal impact on the seagrass classification accuracy. However, the brighter reflectance values reduced LAI retrievals by up to 50% compared to ELH-corrected images and ground-based observations. This study offers a potential correction for LAI underestimation due to incomplete atmospheric correction, enhancing the retrieval of seagrass density and above-ground Blue Carbon from WorldView-2 imagery without in situ observations for accurate atmospheric interference correction.

Evaluation and Comparison of Multi-Satellite Aerosol Optical Depth Products over East Asia Ocean.

The atmosphere over the ocean is an important research field that involves multiple aspects such as climate change, atmospheric pollution, weather forecasting, and marine ecosystems. It is of great significance for global sustainable development. Satellites provide a wide range of measurements of marine aerosol optical properties and are very important to the study of aerosol characteristics over the ocean. In this study, aerosol optical depth (AOD) data from seventeen AERONET (Aerosol Robotic Network) stations were used as benchmark data to comprehensively evaluate the data accuracy of six aerosol optical thickness products from 2013 to 2020, including MODIS (Moderate-resolution Imaging Spectrometer), VIIRS (Visible Infrared Imaging Radiometer Suite), MISR (Multi-Angle Imaging Spectrometer), OMAERO (OMI/Aura Multi-wavelength algorithm), OMAERUV (OMI/Aura Near UV algorithm), and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) in the East Asian Ocean. In the East Asia Sea, VIIRS AOD products generally have a higher correlation coefficient (R), expected error within ratio (EE within), lower root mean square error (RMSE), and median bias (MB) than MODIS AOD products. The retrieval accuracy of AOD data from VIIRS is the highest in spring. MISR showed a higher EE than other products in the East Asian Ocean but also exhibited systematic underestimation. In most cases, the OMAERUV AOD product data are of better quality than OMAERO, and OMAERO overestimates AOD throughout the year. The CALIPSO AOD product showed an apparent underestimation of the AOD in different seasons (EE Below = 58.98%), but when the AOD range is small (0 < AOD < 0.1), the CALIPSO data accuracy is higher compared with other satellite products under small AOD range. In the South China Sea, VIIRS has higher data accuracy than MISR, while in the Bohai-Yellow Sea, East China Sea, Sea of Japan, and the western Pacific Ocean, MISR has the best data accuracy. MODIS and VIIRS show similar trends in R, EE within, MB, and RMSE under the influence of AOD, Angstrom exponent (AE), and precipitable water. The study on the temporal and spatial distribution of AOD in the East Asian Ocean shows that the annual variation of AOD is different in different sea areas, and the ocean in the coastal area is greatly affected by land-based pollution. In contrast, the AOD values in the offshore areas are lower, and the aerosol type is mainly clean marine type aerosol. These findings can help researchers in the East Asian Ocean choose the most accurate and reliable satellite AOD data product to better study atmospheric aerosols' impact and trends.

Non-invasive estimation of in vivo optical properties and hemodynamic parameters of domestic animals: a preliminary study on horses, dogs, and sheep.

Biosensors applied in veterinary medicine serve as a noninvasive method to determine the health status of animals and, indirectly, their level of welfare. Near infrared spectroscopy (NIRS) has been suggested as a technology with this application. This study presents preliminary in vivo time domain NIRS measurements of optical properties (absorption coefficient, reduced scattering coefficient, and differential pathlength factor) and hemodynamic parameters (concentration of oxygenated hemoglobin, deoxygenated hemoglobin, total hemoglobin, and tissue oxygen saturation) of tissue domestic animals, specifically of skeletal muscle (4 dogs and 6 horses) and head (4 dogs and 19 sheep). The results suggest that TD NIRS in vivo measurements on domestic animals are feasible, and reveal significant variations in the optical and hemodynamic properties among tissue types and species. In horses the different optical and hemodynamic properties of the measured muscles can be attributed to the presence of a thicker adipose layer over the muscle in the Longissimus Dorsi and in the Gluteus Superficialis as compared to the Triceps Brachii. In dogs the absorption coefficient is higher in the head (temporalis musculature) than in skeletal muscles. The smaller absorption coefficient for the head of the sheep as compared to the head of dogs may suggest that in sheep we are indeed reaching the brain cortex while in dog light penetration can be hindered by the strongly absorbing muscle covering the cranium.

Relationships between morphology and optical properties of vehicle-emitted soot

Soot emissions from vehicles have effects not only on public health but also on the Earth’s radiative balance. This pollutant is the main absorber of visible solar radiation and is considered to be the second factor contributing to global warming after CO2. Large and compact soot agglomerates have a higher single-scattering albedo than small and irregular ones. Among morphological and optical studies, most of them focus on the effect of the particle size, but not so many on the irregularity of agglomerates. In this work, the methodological approach is based on the combination of original experimental techniques (in-situ measurement of morphological and optical properties of soot particles emitted from a vehicle on a rolling bench) with theoretical developments (using fractal analysis and optical modelling). A typical conventional European road vehicle was used as a soot generator. Individual soot agglomerates were sampled and visualized with transmission electron microscopy (TEM), and their images were subjected to digital treatment and their morphological parameters were used as input for modelling. In addition, a double dilutor-Differential Mobility Analyzer (DMA)-Condensation Particle Counter (CPC)-Cavity Attenuated Phase Shift spectrometer (CAPS) assembly was used, which allows for classification of particles based on their mobility diameter and to simultaneously measure the optical extinction and scattering coefficients of the agglomerates. It was observed that, in general, the diameter of gyration obtained from TEM images underestimate the electrical mobility diameter, especially for large agglomerates. It was also observed that the diameter of primary particles and the power-law prefactor increase with the agglomerate size, while opposite trend was found for the fractal dimension and for the coordination number. Both the mass-specific absorption and scattering cross-sections (MAC and MSC) of agglomerates were observed to decrease with increasing agglomerate size, as consequence of decreasing fractal dimension.

A long path-length optical property measurement device for highly transparent detector media

Measurements of the optical properties of highly transparent liquids are necessary for large-scale detectors that seek to detect optical signatures in kiloton-scale or larger volumes. Detailed understanding of the attenuation and scattering properties of fill media is critical to the ability to accurately simulate detector performance, and yet is often unavailable until in-situ measurements can be performed. Moreover, in-situ measurements may rely on effective attenuation lengths or other approximations to characterize performance, rather than absolute measurements of attenuation and scattering. To better understand the optical properties of potential fill media and purification schemes, a system has been developed which provides simultaneous attenuation and differential scattering cross-section measurements for highly transparent liquids. This horizontal, adjustable path-length “long-arm” system provides excellent isolation from the atmosphere, a high degree of vibration insensitivity, and a simple and reliable method of calibration. Further, scattering measurements can be carried out simultaneously at ports along the beamline equipped with optics allowing the selection of scatter angle and polarization. This enables both reliable quantitative scatter measurements and phase-function separation. This system has been extensively tested using deionized (DI) water as a benchmark, and has demonstrated repeatable measurements of attenuation lengths exceeding 100 m and scattering lengths approaching 1 km.

In-Loco Optical Spectroscopy through a Multiple Digital Lock-In on a Linear Charge-Coupled Device (CCD) Array.

Accurate and reliable measurements of optical properties are crucial for a wide range of industrial and commercial applications. However, external illumination fluctuations can often make these measurements challenging to obtain. This work proposes a new technique based on digital lock-in processing that enables the use of CCD spectrometers in optical spectroscopy applications, even in uncontrolled lighting conditions. This approach leverages digital lock-in processing, performed on each pixel of the spectrometer's CCD simultaneously, to mitigate the impact of external optical interferences. The effectiveness of this method is demonstrated by testing and recovering the spectrum of a yellow LED subjected to other light sources in outdoor conditions, corresponding to a Signal-to-Noise Ratio of -70.45 dB. Additionally, it was possible to demonstrate the method's applicability for the spectroscopic analysis of gold nanoparticles in outdoor conditions. These results suggest that the proposed technique can be helpful for a wide range of optical measurement techniques, even in challenging lighting conditions.

Preparation ZnO:Ag nanoparticles as thin films by Sol-Gel technique for medical application

In this research , silver doped ZnO was prepared as thin films deposited on a glass substrate by sol gel technique and dipping coating. The characterization and antimicrobial prepared thin films was investigated. Structural properties of thin films were studied from measurement of x-ray (XRD), homogeneous and roughness of thin films surface was diagnosed by atomic force microscopy (AFM), optical properties measurement for obtained thin films investigated by used Uv-visible spectra and antibacterial activity test against E-coli bacteria were studied. The results showed antimicrobial activity about 70% of 10%Ag content and activity 10% for 5% Ag content studied.

Transient simulation of laser ablation based on Monte Carlo light transport with dynamic optical properties model

Laser ablation is a minimally invasive therapeutic technique to denature tumors through coagulation and/or vaporization. Computational simulations of laser ablation can evaluate treatment outcomes quantitatively and provide numerical indices to determine treatment conditions, thus accelerating the technique’s clinical application. These simulations involve calculations of light transport, thermal diffusion, and the extent of thermal damage. The optical properties of tissue, which govern light transport through the tissue, vary during heating, and this affects the treatment outcomes. Nevertheless, the optical properties in conventional simulations of coagulation and vaporization remain constant. Here, we propose a laser ablation simulation based on Monte Carlo light transport with a dynamic optical properties (DOP) model. The proposed simulation is validated by performing optical properties measurements and laser irradiation experiments on porcine liver tissue. The DOP model showed the replicability of the changes in tissue optical properties during heating. Furthermore, the proposed simulation estimated coagulation areas that were comparable to experimental results at low-power irradiation settings and provided more than 2.5 times higher accuracy when calculating coagulation and vaporization areas than simulations using static optical properties at high-power irradiation settings. Our results demonstrate the proposed simulation’s applicability to coagulation and vaporization region calculations in tissue for retrospectively evaluating the treatment effects of laser ablation.

Optical property measurements of lithium chloride aqueous solution for a novel solar neutrino experiment

The lithium chloride aqueous solution has great potential to be the detection medium of a novel solar neutrino detector. The nuclide 7Li provides a charged-current interaction channel with a high cross-section for the MeV-scale solar electron-neutrinos, enabling measurement of the solar neutrino spectrum. This work measures the optical properties and the light yields of a saturated lithium chloride solution. After adsorption with activated carbon and recrystallization, the solution shows little absorption in the sensitive wavelength range of the bialkali photomultipliers. The attenuation length is evaluated to reach 50 meters at 430 nm. In addition to being a pure Cherenkov detector medium, a wavelength shifter, carbostyril 124, is added to the LiCl aqueous solution. The compatibility and the enhancement of the light yield are confirmed, enabling the development of a water-based Cherenkov-enhanced lithium-rich detector.

"Optical Property Measurements in Normal Human Brain Tissues: Exploring Discrepancies in the Visible-NIR Region"

"Optical Property Measurements in Normal Human Brain Tissues: Exploring Discrepancies in the Visible-NIR Region"

Profile-based diffuse reflectance corrections for improved optical property measurement of spherical fruit with spatial frequency domain imaging

Diffuse reflectance (Rd), demodulated from spatial frequency domain imaging (SFDI), is strongly influenced by the surface profile of target sample, and the optical properties (absorption coefficient μa and reduced scattering coefficient μ's) extracted from the Rd are prone to large estimation errors caused by curved surface of the fruit. This study proposes a profile-based Rd correction method, aiming to improve the accuracy of optical property measurement for spherical fruit, such as apples, as well as enhance fruit bruise detection through improved optical properties. Firstly, the surface height of the test object was obtained by performing the phase-measuring profilometry (PMP) in SFDI. Secondly, the object surface reflection angle was calculated using the proposed angle calculation method for spherical samples. The Modified Lambertian Correction (MLC) method was then refined to minimize the effect of the incident angle on the Rd correction. The performance of the Rd correction method was validated using standard reflector and Teflon spheres. The results showed that the average error of the PMP measurement with the height range of 0–50 mm was within 1 mm, the relative error of the corrected Rd was within 2 %, and the standard deviation of the Rd for the Teflon sphere was reduced by about 60 % after correction. Finally, the proposed Rd correction method was applied to measure the optical properties of four spherical fruit (‘Golden Delicious’, ‘Red Fuji’ apples, lemons, and oranges). The results revealed that the standard deviations of the measured μa and μ's of the spherical fruit were greatly reduced by about 70 % and 40 % after correction. The improved optical property mappings enhanced the early bruise detection of apples due to the fact that the optical property contrast between the non-bruised and bruised tissues were significantly increased.

(NH4)3(H3O)Zn4(PO4)4: A nonlinear optical zinc orthophosphate crystal

Phosphate crystals are valuable materials according to their diverse structures and physical and chemistry properties. A zinc orthophosphate, (NH4)3(H3O)Zn4(PO4)4, has been obtained via hydrothermal route. It was crystallized in hexagonal space group P63, featuring a three-dimensional (3D) [Zn(PO4)]– anion network built by corner-sharing connected ZnO4 and PO4 tetrahedra. The NH4+ and H3O+ units are located in the six-member cavities of the framework as the balanced cations. (NH4)3(H3O)Zn4(PO4)4 exhibits a moderate and phase matchable second harmonic generation effect (SHG) about 1.4 times of KH2PO4 (KDP), which is the strongest in zinc orthophosphates. Besides structural features, optical properties measurements and theoretical analyses of (NH4)3(H3O)Zn4(PO4)4 were performed.