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Exploring non π-conjugated phosphate birefringent crystal with a large birefringence has been a great challenge. Herein, based on the unique two-dimensional layered structure in KBe2 BO3 F2 (KBBF), two new compounds, Sn2 PO4 I and Sn2 BO3 I, were designed and synthesized successfully, maintaining the layer structural feature and enhancing the optical anisotropy of crystals. In particular, the birefringence of Sn2 PO4 I is larger than or equal to 0.664 @546 nm, which is largest among the reported borates and phosphates, even surpassing commercial birefringent crystals YVO4 and TiO2 . This work indicates that a breakthrough in birefringence of inorganic compound was achieved. Also, it provides a guiding idea for exploring large birefringence materials in the future.

Maximizing the optical anisotropy in birefringent materials has emerged as an efficient route for modulating the polarization-dependent light propagation. Currently, the generation of deep-ultraviolet (deep-UV) polarized light below 200 nm is essential but challenging due to the interdisciplinary significance and insufficiency of high-performing birefringent crystals. Herein, by introducing multiple heteroanionic units, the first sodium difluorodihydroxytriborate-boric acid Na[B3 O3 F2 (OH)2 ]⋅[B(OH)3 ] has been characterized as a novel deep-UV birefringent crystal. Two rare heteroanionic units, [B3 O3 F2 (OH)2 ] and [B(OH)3 ], optimally align to induce large optical anisotropy and also the dangling bonds are eliminated with hydrogens, which results in an extremely large birefringence and band gap. The well-ordered OH/F anions in [B3 O3 F2 (OH)2 ] and [B(OH)3 ] were identified and confirmed by various approaches, and also the origin of large birefringence was theoretically discussed. These results confirm the feasibility of utilizing hydrogen involved heteroanionic units to design crystals with large birefringence, and also expand the alternative system of deep-UV birefringent crystals with new hydroxyfluorooxoborates.

Two-dimensional (2D) perovskites with alternating cations in the interlayer space (ACI) represent a new type of structure with different physical properties compared to the more common Ruddlesden–P...

Two new alkali/alkali earth metal and d10 transition metal mixed cyanurate birefringent crystals, Li2Zn2(H2C3N3O3)2(HC3N3O3)(OH)2·2H2O (I) and BaZn2(H2C3N3O3)2(HC3N3O3)(OH)2·2H2O (II), were synthes...

Looking for ultraviolet (UV) crystals with large birefringence that are easy to grow, and nontoxic, has always been a hotspot in the field of optical materials. Thus, finding novel chromophores and...

Tin(II)oxybromide, Sn14O11Br6 (TOB), was synthesized successfully via the high-temperature solution method in a closed system for the first time. Its structure displays two-dimensional [Sn14O11Br6] layers constructed from highly distorted [SnO3]4− and [SnO2Br]3− polyhedra. Besides, TOB possesses good thermal stability and a birefringence larger than 0.248 at 546.1 nm. First-principles calculations reveal that TOB shows giant optical anisotropy of Δn = 0.265 at 546 nm owing to the superior arrangement of highly distorted Sn–O/Br polyhedra.

General principles of wav plate manufacturing are considered. The possibility of the formation of synthetic optical anisotropy of polymethyl methacrylate (PMMA) by the method of its uniaxial stretching is investigated. The most promising is a method for manufacturing waveplates, which includes the stage of controlled stretching of the polymer material to the required phase shift value, which would generally exclude the stage of machining the plates. The general orderliness of the molecules in the polymer resulting from stretching (orientation) leads to the oriented state of the polymer, and, consequently, to the general anisotropy of the physical and optical properties. In this state, a clearly pronounced uniaxial orientation of polymer chains is observed. As a result, chain macromolecules, randomly (statistically) oriented in the initial PMMA, acquire orientation under the influence of an external directed tensile force. The anisotropy of the optical properties of uniaxially stretched PMMA is manifested in the fact that it has different refractive indices for light polarized parallel to the direction of stretching (orientation) and in the perpendicular direction (birefringence). The regularities of the formation of the synthetic optical anisotropy of PMMA have been studied. The dependences of the birefringence values of uniaxially stretched PMMA on the initial sheet thickness, stretching temperature, and degree of stretching have been measured. It has been shown that the value of birefringence is directly proportional to the thickness of the initial sheet and the degree of stretching and inversely proportional to the stretching temperature. The spectral dependence of the birefringence value is measured. Achromatic and superachromatic waveplates were made from uniaxially stretched PMMA. The spectral characteristics of the phase shift of the manufactured waveplates are given. The availability of the starting material, the technological simplicity of the formation of the initial components for waveplates, as well as the possibility of manufacturing waveplates of large dimensions and high quality, make polymethyl methacrylate with artificially induced anisotropy a promising material for the manufacture of achromatic and superachromatic waveplates.

The main commercially used birefringent oxides α-BaB2 O4 and YVO4 have the birefringences of 0.12 and 0.22. We propose a targeted high-throughput screening system to search birefringence-active functional modules (FMs) and large birefringent materials. A series of π-conjugated C-O units [C2 O4 ]2- , [C2 O6 ]2- , [C4 O4 ]2- , and [C6 O6 ]2- are discovered to be birefringence-active FMs. Theoretical and experimental studies on the crystals with C-O units confirm the feasibility of strategy. Based on this, the C-O containing compounds ranging from deep-ultraviolet to near-infrared region with large birefringence from 0.1 to 1.35 are found, and most of them break through the birefringent limit of oxides. The (NH4 )2 C2 O4 ⋅H2 O crystal is grown and its experimental birefringence is 0.248 at 546 nm, which is identified as a promising UV birefringent crystal. The A-site cations play significant roles in optical properties by influencing the density and arrangement of the C-O units.

Birefringent materials with strong optical anisotropy are indispensable for optoelectronic devices as polarizers, isolators, and beam splitters, etc. Here, a new ionic cocrystal KBr·H3C3N3O3 (I) wa...

We have studied experimentally a series of samples of layered MoS2 flakes with thicknesses varying from 1 to 10 μm and observed their strong in-plane optical anisotropy, which we attribute to the effects of strain in combination with fluctuations in the direction of the C-axis. This optical anisotropy allows us to convert the polarization of transmitted light from linear to circular with the degree up to 15%.

Basing on dilatometric and optical anisotropy studies, we have obtained (x, T)-phase diagram for TlIn(S1–xSex)2 solid solutions in the range 0 ≤ × ≤ 0.25 of selenium concentrations. It has been fou...

Atrioventricular heart valves (AHVs) regulate the unidirectional flow of blood through the heart by opening and closing of the leaflets, which are supported in their functions by the chordae tendineae (CT). The leaflets and CT are primarily composed of collagen fibers that act as the load-bearing component of the tissue microstructures. At the CT-leaflet insertion, the collagen fiber architecture is complex, and has been of increasing focus in the previous literature. However, these previous studies have not been able to quantify the load-dependent changes in the tissue's collagen fiber orientations and alignments. In the present study, we address this gap in knowledge by quantifying the changes in the collagen fiber architecture of the mitral and tricuspid valve's strut CT-leaflet insertions in response to the applied loads by using a unique approach, which combines polarized spatial frequency domain imaging with uniaxial mechanical testing. Additionally, we characterized these microstructural changes across the same specimen without the need for tissue fixatives. We observed increases in the collagen fiber alignments in the CT-leaflet insertion with increased loading, as described through the degree of optical anisotropy. Furthermore, we used a leaflet-CT-papillary muscle entity method during uniaxial testing to quantify the chordae tendineae mechanics, including the derivation of the Ogden-type constitutive modeling parameters. The results from this study provide a valuable insight into the load-dependent behaviors of the strut CT-leaflet insertion, offering a research avenue to better understand the relationship between tissue mechanics and the microstructure, which will contribute to a deeper understanding of AHV biomechanics.

In-plane optical anisotropy has been detected from monolayer MoS2 grown on a-plane (1120) sapphire substrate in the ultraviolet–visible wavelength range. Based on the measured optical anisotropy, ...

Optical anisotropy plays an indispensable role in a variety of optical components. Organic halide perovskites often rely on artificially oriented nanostructures to enhance optical anisotropy due to...

Among layered and 2D semiconductors, there are many with substantial optical anisotropy within individual layers, including group‐IV monochalcogenides MX (M = Ge or Sn and X = S or Se) and black phosphorous (bP). Recent work has suggested that the in‐plane crystal orientation in such materials can be switched (e.g., rotated through 90°) through an ultrafast, displacive (i.e., nondiffusive), nonthermal, and lower‐power mechanism by strong electric fields, due to in‐plane dielectric anisotropy. In theory, this represents a new mechanism for light‐controlling‐light in photonic integrated circuits (PICs). Herein, numerical device modeling is used to study device concepts based on switching the crystal orientation of SnSe and bP in PICs. Ring resonators and 1 × 2 switches with resonant conditions that change with the in‐plane crystal orientations SnSe and bP are simulated. The results are broadly applicable to 2D materials with ferroelectric and ferroelastic crystal structures including SnO, GeS, and GeSe.

The inherited insulating behavior of hexagonal boron nitride (h-BN) monolayer restricts its application in several optoelectronic devices, so finding a technique to reduce the bandgap allows it to possess the semiconducting functionality. Here, an experimentally feasible fluorinated hexagonal boron nitride (FBNF), a structurally, dynamically, and mechanically stable monolayer is reported by using density functional theory calculations. The significant geometrical transformation from planer h-BN to buckled FBNF softens the structure by retaining the mechanical isotropy and structural symmetry. Remarkably, the induced direct bandgap semiconducting behavior after fluorination enhances the optical absorbance and reflectivity reduces energy loss, creates strong optical anisotropy, and makes FBNF monolayer is a proper material in the optoelectronic and nanomechanical applications

Two-dimensional (2D) organic-inorganic hybrid perovskites have attracted growing attention recently due to their naturally formed quantum-well structure, unique photoelectric properties and better environmental stability compared to three-dimensional perovskites. The reduced screening and enhanced Coulomb interaction in 2D perovskites result in the formation of excitonic complexes. While the properties of free excitons have been well investigated, studies on biexcitons remain elusive. Here, we report on the biexcitons in 2D (iso-BA)2PbI4 (BA=C4H9NH3) crystals. The biexciton emission can be observed under a very low excitation power density of 6.4 W/cm2 at 78 K. The biexciton exhibits a large biexciton binding energy of 46 meV due to the large exciton binding energy of (iso-BA)2PbI4. Furthermore, the biexcitons exhibit a favorable polarization orientation, resulting in different anisotropy between biexcitons and excitons. Our findings would motivate more studies on biexcitons in 2D perovskites and pave the way for exploiting the many-body physics for biexciton lasing and optical storage devices.

Collagen fiber networks provide the structural strength of tissues, such as tendons, skin and arteries. Quantifying the fiber architecture in response to mechanical loads is essential towards a better understanding of the tissue-level mechanical behaviors, especially in assessing disease-driven functional changes. To enable novel investigations into these load-dependent fiber structures, a polarized spatial frequency domain imaging (pSFDI) device was developed and, for the first time, integrated with a biaxial mechanical testing system. The integrated instrument is capable of a wide-field quantification of the fiber orientation and the degree of optical anisotropy (DOA), representing the local degree of fiber alignment. The opto-mechanical instrument''s performance was assessed through uniaxial loading on tendon tissues with known collagen fiber microstructures. Our results revealed that the bulk fiber orientation angle of the tendon tissue changed minimally with loading (median ± 0.5*IQR of 52.7° ± 3.3° and 51.9° ± 3.3° under 0 and 3% longitudinal strains, respectively), whereas on a micro-scale, the fibers became better aligned with the direction of loading: the DOA (mean ± SD) increased from 0.149 ± 0.032 to 0.198 ± 0.056 under 0 and 3% longitudinal strains, respectively, p 0.001. The integrated instrument was further applied to study two representative mitral valve anterior leaflet (MVAL) tissues subjected to various biaxial loads. The fiber orientations within these representative MVAL tissue specimens demonstrated noticeable heterogeneity, with the local fiber orientations dependent upon the sample, the spatial and transmural locations, and the applied loading. Our results also showed that fibers were generally better aligned under equibiaxial (DOA = 0.089 ± 0.036) and circumferentially-dominant loading (DOA = 0.086 ± 0.037) than under the radially-dominant loading (DOA = 0.077 ± 0.034), indicating circumferential predisposition. These novel findings exemplify a deeper understanding of the load-dependent collagen fiber microstructures obtained through the use of the integrated opto-mechanical instrument. STATEMENT OF SIGNIFICANCE: In this study, a novel quantitative opto-mechanical system was developed by combining a polarized Spatial Frequency Domain Imaging (pSFDI) device with a biaxial mechanical tester. The integrated system was used to quantify the load-dependent collagen fiber microstructures in representative tendon and mitral valve anterior leaflet (MVAL) tissues. Our results revealed that MVAL's fiber architectures exhibited load-dependent spatial and transmural heterogeneities, suggesting further microstructural complexity than previously reported in heart valve tissues. These novel findings were possible through the system's ability to, for the first time, capture the load-dependent collagen architecture in the mitral valve anterior leaflet tissue over a wide field of view (e.g., 10 × 10 mm for the MVAL tissue specimens). Such capabilities afford unique future opportunities to improve patient outcomes through concurrent mechanical and microstructural assessments of healthy and diseased tissues in conditions such as heart valve regurgitation and calcification.

Perovskite-related compounds are of vital significance in the optical element and laser industry and other fields. Exploring the contributions of microscopic units that form the perovskite framewor...

Although abundant research on the anisotropy of van der Waals (vdW) materials has been published, we undertake an in-depth study of their optical properties as they have an important guiding role for light control in two-dimensional (2D) nanospace. As an example, we study the reflectance of few-layered black phosphorus (BP) in the total internal reflection (TIR) mode in detail. We demonstrate that its optical anisotropy can be changed on a large scale by varying the incident angles, polarization states, and the in-plane rotation angles of the BP samples. Theoretical analysis indicates that the phenomena observed are common to all the atom-thick biaxial crystals, so these conclusions can be widely applied to other anisotropic 2D materials. This research furthers the current understanding of the properties of BP more comprehensively, and provides guidance for developing new optoelectronic applications, especially when BP and other atom-thick biaxial crystals are integrated with TIR devices. Keywords: Black phosphorus, Optical anisotropy, Total internal reflection, Biaxial crystal

In-plane anisotropic two-dimensional (2D) materials, especially black phosphorus and ReS2, have attracted significant interest recently as they can provide one more dimension to manipulate their ph...

Stimuli-responsive soft matters have been recognised by many scientists and engineers as very important because of their inherent characteristics in response to environmental changes. In particular...

We develop a new approach to fabricate three-dimensional (3D) nanocomposite metamaterials formed with the use of a nano-printing technique based on silver nanoink, and we experimentally investigate their optical performance. Nanocomposite metamaterials are formed in the grooves of nanodisks and split-ring resonator (SRR) shapes, and the optical properties of the specimens are evaluated and compared based on the metamaterial sintering conditions. For the nanocomposite nanodisk, two notable resonances are observed in the visible spectral region. In particular, at a wavelength of 430 nm, the absorbance reaches 99.5%, which is greater than the calculated result for bulk silver nanodisk arrays. Via modification of the nanodisk structures, nanocomposite nanodisks based on nanoink can be applied as perfect broadband absorbers. For the nanocomposite SRR, we confirm that there is a unique optical resonance in the SRR before sintering, and the Q-factor is estimated to be 9.1, which is higher than that of the SRR after sintering. In addition, we experimentally demonstrate that the optical properties of the nanocomposite metamaterials can be modulated depending on the choice of nanoink material. Since optical anisotropy is also observed in the nanocomposite SRR, we conclude that the obtained optical spectra are influenced by the shape of the structures.

Some manifestations of optical anisotropy in diamond crystals with defects are due to reduction of the symmetry group of the growth pyramid caused by the removal of the orientation degeneracy of defects during tangential growth. In this case, the point symmetry group of the growth pyramid is determined not only by the symmetry group of the growth face, but also by the symmetry of the defects themselves.

Optical spectra were investigated in a spectral range of (300 - 700) nm for CuAlS2 single crystals. Transmission and wavelength modulated transmission spectra demonstrated presence of some impurity absorption bands in the region of optical transparency of crystals. Optical functions (real and imaginary components of the dielectric function, refractive index and extinction coefficient) have been calculated from the optical reflection spectra by means of the Kramers-Kronig relations. A strong anisotropy and birefringence have been revealed for CuAlS2 crystals. Two isotropic points have been found in (100) oriented platelets around 380 nm and 530 nm. The position of the isotropic point around 530 nm was found to be strongly influenced by the technological conditions of crystal growth and platelet thickness, it being situated at 535 nm for a platelet with thickness of 223 µm. An optical band-pass filter was constructed with such a platelet placed between two Gran-Thompson prism crossed polarizers.

The possibility for creation of the optical anisotropy with small periodicities up to nano-scale in amorphous materials is perspective in future for obtaining of different miniature elements for optoelectronics. In this paper the investigation results of the impact of rare-earth doping upon the process of the creation and also on the properties of the photo-induced micro-periodical anisotropy in different samples are presented. The influence of the variations of the chemical rare-earth components is analyzed and the physical mechanisms are discussed.

A chiral polythiophene surfactant based on poly(3-(S)-2-methylbutylthiophene) ((S)-P3MBT) with a semifluoroalkyl group at one end of the main chain was synthesized and used to form surface-segregated monolayers (SSMs). Films of pure (S)-P3MBT mainly adopted the edge-on orientation, whereas (S)-P3MBT films with a SSM of the polymer surfactant (S)-P3MBT-F17 contained a large proportion of end-on-oriented polythiophene, both at the surface and inside the films. The thin films with the SSM showed circular dichroism signals, with the sign opposite to those observed in (S)-P3MBT films. These findings suggest that the orientation-controlled SSM layers induced changes in the packing of the polymer aggregates in the films, resulting in a dramatic change in the excitonic interactions of the chiral semiconducting polymers.

In this study, the birefringence (delta n) and macroscopic order parameter (Q) of lyotropic nematic calamitic (N-C) mesophase were obtained in the reentrant isotropic (I-RE)-N-C-isotropic (I) phase transition range by only examining its optical transmittance under a polarising microscope. Moreover, the microscopic order parameter (S) was found by obtaining absorption coefficients from these transmittances. Generally, the macroscopic order parameter was larger than the microscopic one. The difference between them was small near the I-RE-N-C phase transition and the maximum birefringence region whereas it was relatively high near the N-C-I phase transition.

Existing techniques for the analysis of the optical anisotropy of myocardium sections are described and explained, with examples of the implementation and results.

We demonstrate phase-only tuning of optical metasurfaces in the full 2p-range by controlling the optical anisotropy of their surroundings. The concept is exemplified in a liquid crystal infiltrated metasurface tuned by the temperature and bias-voltage.

This chapter provides a brief presentation of dilute mixtures of simple liquid crystal (LC) phases and diverse nanoparticles (NPs). A unique combination of softness, liquid behavior, and optical anisotropy introduces LCs by themselves into a wide variety of applications, in particular, in electro-optics (e.g., liquid crystal display technology). Recently, LCs have moved into the attractive provinces of nanoscience and nanotechnology, which increases complexity of resulting structures, often introducing new material properties and functionalities. Consequently, such configurations enormously widen window of possible LC-based applications. In this contribution, representative examples of different types of NPs within several types of LC configurations are presented. Dispersions of nanomaterials of various dimensions (zero, one, and two) in LCs yields either effective systems with anomalously enhanced or new material properties. Phase behavior of LCs, NPs self-assembly and alignment in liquid crystalline media, synthesis of NPs by using LCs as templates or precursors are discussed. The importance of NPs–LC synthesis and interactions to obtain desired synergetic properties is highlighted.

The basic methods for diagnostics of the myocardium using optical anisotropy parameters are established.

The optical properties of mono‐ and trilayer graphene on SiO2/Si substrate are studied at hydrogen Lyman‐alpha (121.6 nm) spectral line for the first time. The optical anisotropy of graphene at this wavelength is experimentally demonstrated by retrieving the anisotropic “effective” optical constants. The results confirm that the axis of symmetry is nearly perpendicular to the surface and coherently related to the π‐orbitals’ structural orientation. Furthermore, it is observed that graphene strongly affects the performances of the substrate by inducing a pseudo‐Brewster angle downshift, which depends on the number of graphene layers. This finding is in contrast with what occurs in the visible spectral range, where the upshift of the pseudo‐Brewster angle is experienced in similar samples.

Tungsten oxide WO3-x is a transition metal oxide and a wide bandgap semiconductor, with a wide range of possible optical and photonic applications. In dependence on the fabrication techniques different stoichiometric ratios (x) and crystalline phases are obtained, which end up with an overall polymorph and extremely versatile material, characterized by tailorable dielectric properties. In particular, WO3-x thin film deposition by Radio-Frequency (RF) sputtering techniques provides a precise control of thickness, composition and nanostructure. In this work we introduce and discuss a specific process of deposition, that is magnetron RF-sputtering as a suitable way to grow WO3-x thin films with selected properties. Possibility of integrating WO3-x thin film on to one-dimensional (1D) photonic crystal structures is also explored. Films are transparent in the near and short-wavelength infrared optical spectral range. Their quality is assessed by morphological, structural and compositional characterizations. Dielectric properties are characterized by optical spectroscopy and ellipsometry, the latter also evaluates the degree of optical anisotropy of thin films in their crystalline phase. An 1D photonics bandgap structure is designed, formed by a SiO2–TiO2 multilayer and capped with a 450 nm-thick transparent WO3-x film, so that surface confinement and local enhancement of the optical field at 1416 nm in the topmost WO3-x layer is obtained.

The thermal lens was investigated in C a F 2 and T b 3 G a 5 O 12 cubic crystals with [001] crystallographic axes orientation and in magneto-optical glass MOG103 by the method of phase-shifting interferometry. It was demonstrated experimentally that the thermal lens has astigmatism determined by the incident radiation polarization state and by the optical anisotropy parameter ξ . A method of ξ determination by measuring thermal lens astigmatism in cubic crystals with [001] orientation was proposed and verified. It was shown that thermally induced depolarization and the amplitude of phase astigmatism depend on the position of the crystal with [001] orientation in antiphase.

Two yellow bis-azo dyes containing anthracene and two azodiphenylether groups (BPA and BTA) were prepared, and an extensive investigation of their physical, thermal and biological properties was carried out. The chemical structure was confirmed by the FTIR spectra, while from the UV&ndash, Vis spectra, the quantum efficiency of the laser fluorescence at the 476.5 nm was determined to be 0.33 (BPA) and 0.50 (BTA). The possible transitions between the energy levels of the electrons of the chemical elements were established, identifying the energies and the electronic configurations of the levels of transition. Both crystals are anisotropic, the optical phenomenon of double refraction of polarized light (birefringence) taking place. Images of maximum illumination and extinction were recorded when the crystals of the bis-azo compounds rotated by 90&deg, each, which confirms their birefringence. A morphologic study of the thin films deposited onto glass surfaces was performed, proving the good adhesion of both dyes. By thermal analysis and calorimetry, the melting temperatures were determined (~224&ndash, 225 &deg, C for both of them), as well as their decomposition pathways and thermal effects (enthalpy variations during undergoing processes), thus, good thermal stability was exhibited. The interaction of the two compounds with collagen in the suede was studied, as well as their antioxidant activity, advocating for good chemical stability and potential to be safely used as coloring agents in the food industry.

The results of a study of the forensic medical efficiency of differential diagnosis of cases of alcohol and carbon monoxide poisoning by diffuse tomography of the distribution of the magnitude of fluctuations of linear and circular birefringence of biological preparations are presented: Mueller differential matrix mapping of the polycrystalline component of histological sections of the brain, myocardium, adrenal glands, liver and polycrystalline blood films of the deceased with the algorithmic determination of a series of diffuse tomograms - polarization reproduction of coordinate distributions of fluctuations of linear birefringence of fibrillar networks (FLB); Intergroup statistical differentiation of diffuse FLB tomograms by the optically anisotropic component of histological sections of the brain, myocardium, adrenal glands, liver and polycrystalline blood films of the deceased due to coronary heart disease, alcohol and carbon monoxide poisoning; Establishment of the diagnostic strength of the diffuse tomography method by determining the operational characteristics (sensitivity, specificity and balanced accuracy) in the forensic medical differentiation of histological sections of the brain, myocardium, adrenal glands, liver and polycrystalline blood films of the dead of all groups.

For differential diagnosis of severity of the septic process, the method of mapping vector-parametric microscopic images of the polycrystalline component of histological sections of the internal organs of rats was used. A statistical analysis of the distribution of the number of characteristic values of the Stokes vector of polarizing microscopic images of histological sections of the internal organs of laboratory rats was carried out. The relationships between the values of statistical moments of the 1st - 2nd orders of magnitude characterizing the distribution of the number of characteristic values of the Stokes vector of polarizing microscopic images of histological sections of the internal organs of laboratory rats and the severity of the septic process are determined. Quantitative parameters that are most sensitive to septic conditions have been established, which ensure the implementation of statistically confidance differentiation of histological sections of the internal organs of laboratory rats. From the standpoint of evidence-based medicine, the operational characteristics of the diagnostic forces of the vector-parametric microscopy method are established with an estimate of the number of characteristic values of the fourth Stokes vector of polarization images of histological sections of the internal organs of laboratory rats.

This section contains the results of a study of the relationships between the 3D distributions of the optical anisotropy parameters of polycrystalline networks of biological fluid films of different biochemical composition and the layered phase sections of volume distributions of the magnitude and parameter phase of the "two-point" Stokes vector of the microscopic image.

1. Development of a structural-logical scheme and experimental testing of methods and means of diffuse tomography new in forensic practice for reproducing fluctuations in the magnitude of linear and circular birefringence and dichroism of the polycrystalline structure of histological sections of the brain. 2. Experimental determination of a set of maps and histograms fluctuation distributions of linear (FFLB) and circular (FFCB) birefringence and dichroism (FALD and FACD) for differential diagnosis of traumatic hemorrhage, cerebral infarction ischemic and hemorrhagic genesis using diffuse tomography of polycrystalline structure of histological sections of the brain. 3. Information analysis to determine the operational characteristics of the force (sensitivity, specificity and balanced accuracy) of the diffuse tomography method.

We establish a simple quantitative criterium for the search of new dielectric materials with high values of refractive index in the visible range. It is demonstrated, that for light frequencies below the bandgap, the latter is determined by the dimensionless parameter η calculated as the ratio of the sum of the widths of conduction and valence bands and the bandgap. Small values of this parameter, which can be achieved in materials with almost flat bands, lead to dramatic increase of the refractive index. We illustrate this rule with a particular example of rhenium dichalcogenides, for which we perform ab initio calculations of the band structure and optical susceptibility and predict the values of the refractive index n > 5 $n{ >}5$ in a wide frequency range around 1 eV together with comparatively low losses. Our findings open new perspectives in search for the new high-index/low-loss materials for all-dielectric nanophotonics.

This paper presents a new reflection-only set-up for characterizing the properties of an anisotropic PEC-backed materials. Albeit, the reflection-only methods are established long ago, they are not elaborated appropriately for retrieving industrial anisotropic materials. In spite of other researches, this method is capable to determine tensors of both permittivity and permeability of an anisotropic PEC-backed material. In contrast to similar researches, this method is mathematically simple and easy to implement. Tensors of epsilon and mu of PEC-backed sample are characterized by rotating sample and measuring reflection coefficient in various configuration. Not measuring the transmission, in order to provide enough equations, the higher order mode of the waveguide is employed. A three-port probe is designed for this goal and optimized to excite the TE(10)and TE(20)modes simultaneously. Good agreement of retrieved parameters from experimental measurements with those of actual ones shows the reliability of this set-up for characterization of PEC-backed anisotropic composites.

The preservation state of parchment primarily depends on the structure of the collagen fibre network, which in turn is responsible for optical anisotropy, i.e. birefringence. Polarised light microscopy can therefore be used as a non-invasive technique that allows recording of birefringence distribution in the parchment, which directly relates to stress–strain distribution. Using samples from diverse sources (commercial parchment, parchment used by restorers for book binding, and parchment fabricated for the purpose of this study), we assessed the capability of polarised light microscopy for various diagnostics. We performed, for instance, identification of gelatinised regions, layered or fibrous regions in parchment cross section, qualitative analysis of parchment fat content (lipids), observation of stress-induced patterns resulting from tensile tests, and observation of water diffusion. These proof-of-principle experiments extend the capability of polarised light microscopy far beyond its common use and open the path to its deployment in conservation studies.

In this article, a combined approach for studying the optical anisotropy of porous thin films obtained by the glancing angle deposition is presented. This approach combines modeling on the atomistic and continuum levels. First, thin films clusters are obtained using the full-atomistic molecular dynamics simulation of the deposition process. Then, these clusters are represented as a medium with anisotropic pores, the shapes parameters of which are determined using the Monte Carlo based method. The difference in the main components of the refractive index is calculated in the framework of the anisotropic Bruggeman effective medium theory. The presented approach is tested and validated by comparing the analytical and simulation results for the model problems, and then is applied to silicon dioxide thin films. It is found that the maximum difference between the main components of the refractive index is 0.035 in a film deposited at an angle of 80&deg, The simulation results agree with the experimental data reported in the literature.

Controllable optical properties are important for optoelectronic applications. Based on the unique properties and potential applications of two-dimensional Janus WSSe, we systematically investigate the strain-modulated electronic and optical properties of WSSe bilayer through the first-principle calculations. The preferred stacking configurations and chalcogen orders are determined by the binding energies. The bandgap of all the stable structures are found sensitive to the external stress and could be tailored from semiconductor to metallicity under appropriate compressive strains. Atomic orbital projected energy bands reveal a positive correlation between the degeneracy and the structural symmetry, which explains the bandgap evolutions. Dipole transition preference is tuned by the biaxial strain. A controllable transformation between anisotropic and isotropic optical properties is achieved under an around − 6%~− 4% critical strain. The strain controllable electronic and optical properties of the WSSe bilayer may open up an important path for exploring next-generation optoelectronic applications.