Phenomenon Of Total Internal Reflection Research Articles

Fundamentals of Determination of the Biological Tissue Refractive Index by Ellipsoidal Reflector Method

This paper presents the theoretical fundamentals, prerequisites for creation, and peculiarities of modeling a new method for determining the refractive index of biological tissues. The method uses a mirror ellipsoid of revolution as an optical element to ensure total internal reflection phenomena. This paper thoroughly analyzes the differences in the refractive index of healthy and pathological tissues on a biometric diagnostic basis. The analysis is used to model the measurement setup’s parameters. This paper also considers various methods of determining the refractive index of biological tissues based on different principles of physical optics, such as interferometry, refractometry, ellipsometry, and goniophotometry. It systematizes typical optical elements of total internal reflection that can be used in goniophotometry. It justifies the selection of the element base for the goniometric installation based on the ellipsoidal reflector method. A simulation of the installation operation was carried out for various parameters of the ellipsoidal reflector, ensuring the measurement of the biological tissue refractive index from 1.33 to 1.7. This paper also proposes a constructive solution for manufacturing an ellipsoidal reflector of the required configuration.

Investigation of a highly-sensitive aluminum-based plasmonic device using antimonene for sensing applications

Aluminum (Al) has gained popularity for surface plasmon resonance-based applications due to its affordability and compatibility with CMOS technology at the nanoscale. Over angle-interrogation mode, plasmonic interactions occurring at the metal-dielectric junction, are the outcomes of the attenuated total internal reflection phenomenon. Modified Al-based Kretschmann configuration results in phase-matching conditions that are seen as resonant points in the reflection characteristics. In our work, we have engineered an Al-based plasmonic device utilizing Antimonene as a 2D nanomaterial for bio-sensing purposes in the Near-Infrared (NIR) spectral domain. The study investigates the performance of Surface Plasmon Resonance (SPR) based refractive index sensor using different 2D nanomaterials with an optimized Al thickness of 30 nm. A comparative analysis of Al-based Kretschmann configurations in the presence of Graphene, Black Phosphorus, MXene, and Antimonene is presented using engineered intermediate layers. It is observed that the Al-antimonene-based plasmonic device exhibits improved sensing parameters in the NIR optical window.

Inversion of extinction coefficient and refractive index of variable transparency solid–solid phase change material based on a hybrid model under real climatic conditions

The application of phase change materials (PCMs) in transparent building envelopes has received extensive attention. However, most of the studies have simplified the optical parameters of the PCMs in their models. Because the temperature of PCMs cannot be controlled when using the spectrophotometer, it is difficult to measure the changing trend of optical parameters versus temperature. In this study, an inverse approach was developed for the first time, based on a hybrid model, to fit the accurate function expressions between the extinction coefficient and the refractive index of PCM and temperature. The hybrid model was a combination of experimental data-driven, mathematical models, and multi-objective optimization. Firstly, a test platform of the variable transparency solid–solid PCM (VTSS-PCM) window was constructed and tested last for a year to collect the datasets. Secondly, the photo-thermal coupling model of the window was established, in which the hysteresis and the total internal reflection phenomena were considered. Then, taking the unknown coefficients in the function expressions as decision variables, a bi-objective optimization model was built, based on two error statistics of experimental values and simulated values, and solved by genetic algorithm. Finally, the inversion dataset and validation dataset were used to prove the reliability of the inversion results. The results showed that the refractive index and extinction coefficient of the VTSS-PCM were 1.11 and 25.73 m−1 in the transparent phase, and 5.33 and 152.82 m−1 in the opaque phase. Within the phase change temperature range, the function expressions between the refractive index and extinction coefficient and the temperature were obtained respectively. The verification results showed that the function curves obtained by inversion were reliable. No matter whether the inversion dataset or validation dataset was used as input, the values of RMSE and CV(RMSE) met the ASHRAE Guidelines. The inversion method is meaningful to get the optical parameters of PCMs, to accurately evaluate the performance of PCM-built envelope.

Generalized total internal reflection at dynamic interfaces

Recent research developments in the area of spacetime metamaterial structures and systems have raised new questions as to how the physics of fundamental phenomena is altered in the presence of spacetime modulation. In this context, we present a generalized and comparative description of the phenomenon of total internal reflection (TIR) at different dynamic interfaces. Such interfaces include, beyond the classical interfaces corresponding to the boundaries of moving bodies (moving interface--moving matter systems), interfaces formed by a traveling-wave step modulation of an electromagnetic parameter (e.g., refractive index) (moving interface--stationary matter systems) and fixed interfaces between moving-matter media (stationary interface--moving matter systems). We first resolve the problem using the evanescence of the transmitted wave as the criterion for TIR and applying the conventional technique of relative frame hopping (between the laboratory and rest frames), which results in closed-form formulas for the relevant critical (incidence, reflection, phase refraction, and power refraction) angles. We then introduce the concept of catch-up limit between the dynamic interface and the transmitted wave as an alternative criterion for the critical angle. We use this approach both to analytically verify the critical angle formulas, further validated by full-wave (FDTD) analysis, and to explain the related physics, using Fresnel-Fizeau drag and spacetime frequency transition considerations. These results might find various applications in ultrafast optics, gravity analogs, and quantum processing.

Ellipsometry of thin films of biological objects under conditions of total internal reflection

An analysis of the ellipsometric parameters of the reflected light from the prism test material air system is carried out when circularly polarized light is incident on it under the conditions of the onset of the phenomenon of total internal reflection. At the onset of total internal reflection, the ellipsometry parameter shows high variability with the angle of incidence, in contrast to the parameter r0. It is shown that TIR occurs when the angle of incidence is not equal to the critical angle of the adjacent media for two different materials, these angles differ from each other. In the case of a film, the TIR phenomenon occurs at an angle equal to the critical angle at the prism-air interface and does not depend on the film material. The results obtained show the high efficiency of using the ellipsometric method together with circularly polarized incident radiation for diagnostics of thin films made of biological material.

Optically Transparent Graphene Flakes as Nanogenerator of Microbubbles for Random Lasing in Weakly Scattering Regime

The minimization of photon loss is one of the significant challenges in designing efficient random lasers (RLs). Herein, the demonstration of a 4‐(dicyanomethylene)‐2‐methyl‐6‐(4‐dimethylaminostyryl)‐4H‐pyran (DCM) dye‐based RL is made by the employment of an innovative adaptive feedback mechanism through the use of a fundamental phenomenon of total internal reflection of light in the microbubbles, generated photothermally in the presence of graphene flakes (GFs). Interestingly, here, GFs have acted simultaneously as passive scatterer and thermocatalyst for in situ generation of microbubbles in the liquid suspension of dye molecules. It is demonstrated by a simple pump‐probe photography experiment that during RL emission, the transport of photons is occurring via weak scattering in GFs followed by total internal reflection on microbubbles. Thus, RL emission at 638.4 nm is achieved with a low lasing threshold, linewidth, and moderately high quality factor of 84 W cm−2, 2 nm, and 1127, respectively. The performances of GFs in RL generation are found to be superior in comparison with those of spherical TiO2 and Ag nanoparticles. The strategy is a contemporary approach for applying a 2D material as a nanogenerator of microbubbles to achieve improved RL emission in the weakly scattering regime using an adaptive feedback approach.

The Analysis of Light Intensity Transmission Coefficient Through Plastic Fibers for the Design of Closed Room Lighting without Electricity

The phenomenon of total internal reflection can be used to guide the light to be transmitted from one place to another, it is applied to the guiding principle of light in fiber optics. A fiber rope made of clear plastic material with a uniform refractive index, when one end fired a beam of light then the light will be forwarded along the strap so that out at the other end. This principle can be applied as a lighting source in a closed room by passing light from the outdoors by using plastic fiber, so it doesn’t need the electricity. In this study, theoretical analysis of the percentage of the intensity of light transmitted by the fiber plastic succeed as a function of the refractive index and determine the transmission coefficient for some plastic seeds are eligible to be used as a plastic fiber light successor. From the results of deriving the equation, the light transmission coefficient of plastic is and the terms of plastic seeds that can be used as a plastic fiber are having a refractive index . Based on refractive index data from profesionalplastics, the maximum transmission coefficient value for Ethylene Tetrafluoro Ethylene Copolymer is 82.23% and the minimum transmission value of Fluorinated Ethylene Propylene Copolymer is 55.99%.

Новый метод измерения показателя преломления текущей жидкости

The necessity of developing a new method for measuring the refractive index of a liquid in a turbulent mode of its flow in a pipeline is substantiated. A new method for measuring the refractive index of a medium n is presented. For its practical implementation, a new design of a flow-through refractometer has been developed, which makes it possible to measure n in both laminar and turbulent fluid flow. A new design of the optical part of the refractometer is considered. A new way of placing it on the vertical section of the pipeline for measuring n is proposed. All this makes it possible to make insignificant the influence on the measurement result of n flowing liquid of errors associated with multiple reflections of laser radiation from optical elements, with the formation of voids or vortex flows in the pipeline and with temperature fluctuations. In the design of a refractometer with a new method for measuring n, there are no restrictions on determining the value of n of a flowing liquid, in contrast to the used industrial flow-through refractometers, the principle of which is based on the phenomenon of total internal reflection of laser radiation at the interface of two media. The results of experimental studies of various media are presented.

Acrylic Panels Applications as Building Materials and Daylighting Devices

Enormous studies have been conducted to enhance the daylighting utilization in buildings either by direct lighting techniques, lighting reflection systems, lighting transporting systems, or by light tracking systems. The current research aims at evaluating acrylic panels as a light transmitting medium and studying their possible applications to bring natural light to inner spaces due to the lack of researches on acrylic sheets. Acrylic panels utilize the total internal reflection phenomena to convey the light for long distances. The research depended on real experiments and real measurements by using physical models with real dimensions. Many design variables had been studied like thickness, length, orientations and surroundings materials. The long-term measurements showed that acrylic panels could transmit light 8 times greater than the glass sheets, and the thickness of 20 mm for the acrylic glass panel, 30 cm collector length, 20cm diffuser length, with a steel surrounding on both sides show a great potential to transmit light up to 3493.3 lux at the diffuser during the peak hours in summer. While the results of the real size daylighting chamber show that the acrylic glass could transmit light up to 580 lux during the peak hours in summer. The study showed that the number and the distribution of acrylic glass panels in the space depend on the needed illuminance task levels. Moreover, the acrylic glass panels could be easily integrated with building materials in walls and roofs.

A generalized model of the Kapitza resistance

This work devoted to a new generalized model of Kapitza conductance. At present, the problem of the development of the theory of contact resistances between solids is particularly relevant due to growth of nanotechnology, where it plays an important and sometimes main role in the heat transport. Presented model takes into all specified properties of acoustic waves. First of all, it is refraction and reflection of acoustic waves that caused simultaneously both longitudinal and transverse waves. Secondly, it is considered the phenomenon of total internal reflection, which makes a significant contribution to the Kapitza resistance. These facts totally change the formulation of the problem, especially, the boundary conditions on the contact surface (interface). Results shows a good agreement with the experimental data, better than in previous works.

Sensitivity of an optical sensor based on capillary microresonator for the measurement the hydrostatic pressure in microfluidics

In this investigation, we report the study of an optical device for the measurement of hydrostatic pressure in fluids. The device studied is a sensor based on a dielectric optical resonator in the form of a capillary that confines the light in its interior through the phenomenon of total internal reflection. In the analytical study of the sensor, the excitation of the azimuthal modes WGMs inside the resonant cavity is considered, so that their sensitivity to changes in the hydrostatic pressure was analyzed as a function of the displacement of wavelengths of resonances in the cavity.

Maximized vertical photoluminescence from optical material with losses employing resonant excitation and extraction of photonic crystal modes

Abstract Optical losses of a host material together with the total internal reflection phenomenon can significantly reduce photoluminescence external quantum efficiency of embedded light-emitters. This is not only the case for light-emitting color centers in thin layers of nanocrystalline diamond, but also for silicon nanocrystals in silica dioxide matrices and for some types of perovskite materials. Here, we show that a significant boost (more than 100-fold enhancement) of the directional light emission efficiency from light-emitters in diamond can be achieved by using two-dimensional photonic crystal slabs (PhCs) to extract the light emission into vertical direction (resonant extraction) and at the same time to couple the excitation beam into the structure (resonant excitation). We have further shown that this so-called resonant extraction and excitation scheme provides the highest enhancement when the overlap between the electric field distribution of extraction leaky mode and the region of the excited light-emitters is maximized. This can be achieved by using the same type of the photonic mode for both extraction and excitation, and by optimizing the thickness of a diamond layer. The usage of the same type of modes appears to be more significant than tuning of the Q-factors of the excitation and extraction leaky modes individually. The results of our measurements are supported by the outputs of computer simulations. Our findings may be helpful in designing future PhCs for extraction of luminescence originating from various optoelectronic and sensor devices making use of the unique properties of the diamond. Moreover, our concept can be easily extended to other light-emitting materials with optical losses.

Capillary resonator as optical sensor for the measurement of the hydrostatic pressure. A theoretical study of its sensitivity

We report the study of an optical device for the measurement of hydrostatic pressure in fluids. The device studied is a sensor based on a dielectric optical resonator in the form of a capillary that confines the light in its interior through the phenomenon of total internal reflection. For the analytical study of sensitivity, we have considered the solution of the Helmholtz scalar equation for the case of a resonant cavity in form of cylinder composed of three layers with different refractive index. During the study, the excitation of the Whispering Gallery Modes WGMs on a transverse plane along the axial axis of the cavity is studied and the equation of eigenvalues that has information of the wavelengths of resonances for the TE and TM modes were obtained from the resonance conditions. To determine the sensitivity of the device, the shift of the wavelengths of resonances as a function of the internal pressure in the cavity were analyzed. The results show that it is possible to increase the sensitivity of the microresonator when the wall thickness of the cavity is thin, and the maximum diameter is increased.

Design of a frequency filter on the basis of the total internal reflection phenomenon

Design of a frequency filter on the basis of the total internal reflection phenomenon

Review of optical fibers-introduction and applications in fiber lasers

Abstract The optical fibers which are considered as waveguides can be applied to light transmission applications. The core part of the optical fiber is surrounded by a glass or plastic layer called cladding which is characterized by the refractive index that is lower compared to the core refractive index. The total internal reflection phenomena are necessary for the fine confinements of the light within the waveguide. Basically, optical fibers can be categorized based on the structure, modes number, refractive index profile, dispersion, signal processing ability, and polarization. In this report, we focus on the first three common types of optical fibers. As a common application of the fibers, these can be used in fiber lasers to create and amplify a narrow intense beam of coherent and monochromatic light. Fabrication of optical fiber involves three stages such as the preform formation. Modified chemical vapor deposition (MCVD) method is a known technique, which can be used to fabricate the optical fibers. Optical fiber sensors are well known for wide range applications in optics and photonics. As a sensing application, optical biosensors can be made based on the refractive index changes that used widely for detection of biomolecules in their natural forms.

Numerical modelling of the internal reflection and Goos-Hänchen shift of electromagnetic beam wave

Abstract Total internal reflection of plane waves is a well-known phenomenon. Some new aspects of the numerical treatment of the total internal reflection phenomena, concerning the beam-wave, are discussed.

Suppression of parasitic modes in a YAG:Nd slab laser using selective coating

The use of selective coating for suppression of parasitic modes in a slab laser with a YAG:Nd active element is investigated. Various designs of selective coatings are analyzed and optimized, based on the phenomenon of total internal reflection. The possibility of implementing a selective coating based on thin-film materials titanium, silicon dioxide, and aluminum oxide is demonstrated.

Broadband SHG based on TIR-QPM in a multi-tapered slab – a comparative study with two isotropic semiconductor materials

In this paper, we have done a comparative analysis on the performance of broadband second harmonic generation (SHG) using the concept of Total-Internal-Reflection-Quasi-Phase-Matching in near-infrared (NIR) region when the isotropic multi-tapered semiconductor slab is made of Zinc Telluride (ZnTe) and Cadmium Telluride (CdTe) semiconductors. MATLAB simulation has been carried out to obtain the conversion efficiency and 3db bandwidth when the slab is incident with a broadband fundamental laser radiation and the phenomenon of total internal reflection (TIR) takes place within the slab of 10 mm length. We have also considered the absorption losses, reflection losses and Goos-Hänchen (GH) shift in this process. The effects of variation in temperature, variation of the tapering angles of the slab which is made of semiconductor has been studied for second harmonic radiations in both CdTe and ZnTe crystals. Optimizing these parameters, we can design a wider broadband frequency converter with acceptable peak efficiency.

Use of the Phenomenon of Total Internal Light Reflection for Diagnostics of Sea Wind Waves

We develop a mathematical model for the formation of underwater images of a perturbed sea surface. On the basis of this model, a method for determination of statistical spatio-temporal characteristics of wind waves, which uses the phenomenon of total internal light reflection at the water—air interface, is proposed.

Study of a coronagraphic mask using evanescent waves.

The evanescent wave coronagraph (EvWaCo) is a specific kind of band-limited coronagraph using the frustrated total internal reflection phenomenon to produce the coronagraphic effect (removing starlight from the image plane in order to make the stellar environment detectable). In this paper, we present a theoretical and experimental study of the EvWaCo coronagraphic mask. First, we calculate the theoretical transmission and we show that this mask is partially achromatic. Then, we present the experimental results obtained in unpolarized light at the wavelength λ≈900 nm and relative spectral bandwidth Δλ/λ≈6%. In particular, we show that the coronagraph provides a contrast down to a few 10-6 at an angular distance of about ten Airy radii.