TE Components Research Articles

Resource productivity and determinants of technical efficiency among cassava farmers’ in north central, Nigeria

This research analyzed resource productivity and determinants of technical efficiency among cassava farmers in North Central, Nigeria. This research employed a multi-stage sampling technique. Primary data were used based on a well-designed questionnaire. Inferential and descriptive statistics were employed for data analysis. The results of resource productivity of inputs show that cassava cuttings and fertilizer have the highest and lowest elasticities, respectively. The mean-TE (Technical Efficiency) score of 74% (0.74) indicates that an average smallholder cassava producer in the sample needs about 26% (0.26) additional inputs to get to the frontier. In the TE components, the coefficients of labour, and fertilizers are significant different from zero at 1% probability level. The coefficients of agrochemicals, land inputs are significantly different from zero at 5% probability level, while the coefficient of cassava cuttings are significant different from zero at 10% probability level. In the TIE (technical inefficiency), component the coefficients of age, credit received, members of cooperatives are significant different from zero at 1% probability level. The policy formulations should be directed towards considering technological substitutions and mechanized agriculture. Excessive labour supply, characteristics of the developing agriculture in sub-Saharan Africa, could be pushed into the secondary sector of the Nigerian economy such as the cassava processing industry, therefore generating income, employment and maintaining Nigeria in the first (1st) position in the world ranking in term of cassava output. Also, it is recommended that improved cuttings, agrochemicals, and fertilizers should be made available to cassava farmers at appropriate time to increase productivity. Furthermore, credit should be made available to cassava farmers at a single digit interest rate, devoid of cumbersome administrative procedures. Keywords: Resource productivity, technical efficiency, cassava farmers, stochastic frontier model, Nigeria

Elucidating temperature-dependent local structure change and optical properties in GeTe phase-change material

Phase-change memory emerges as a top contender for non-volatile data storage applications. We report here a systematic change in local structure and crystallization kinetics of binary GeTe thin films using temperature-dependent resistivity measurements, which offers single-stage crystallization at around 187 °C, corroborated with x-ray diffraction. Furthermore, the change in chemical bonding upon crystallization is determined through x-ray photoelectron spectroscopy core level spectra, which reveals the existence of Ge and Te components that align with the GeTe crystal structure. Also, an investigation was carried out employing a UV–Vis–NIR spectrophotometer to explore the evolution of optical bandgaps (Eg), Tauc parameter (B) representing the local disorder, and Urbach energy (Eu) of the GeTe material, as it undergoes the transition from a disordered amorphous state to a crystalline state. As crystallization progresses, a consistent shift of Eg from 0.92 to 0.70 eV corresponds to as-deposited amorphous at room temperature and crystalline at 250 °C, respectively. In addition, the reduction in Eu (from 199.87 to 141.27 meV) and a sudden increase of B around crystallization temperature is observed upon increasing temperature, indicating direct observation of enhanced medium-range order and distortion in short-range order, respectively, in GeTe thin films, revealing improved structural and optical properties. These enhancements make the GeTe material ideal for data storage applications of phase-change memory for next-generation computing technology.

Compact polarization beam splitter based on metal-capped thin-film LiNbO3-on-insulator plasmonic waveguide

A compact polarization beam splitter based on a triple-waveguide plasmonic directional coupler is proposed and modeled. The directional coupler consists of two usual lithium-niobate-on-insulator (LNOI) ridge waveguides and a metal-capped plasmonic LNOI waveguide located between them. It utilizes stronger polarization dependence of modal birefringence of a plasmonic waveguide. By appropriately designing the plasmonic waveguide geometry, the TM component wave meets the resonant coupling condition and outputs at cross port. Instead, the TE component wave does not meet the resonant coupling condition, cannot be resonant in the triple-waveguide directional coupler and outputs at through port directly. Excellent performance is expected for an optimal device. First, the device shows an ultra-high polarization extinction ratio(PER) of 28.3 dB and an ultra-low insertion loss(IL) of 0.06 dB for the TE-polarized wave, and of 31.7 dB and of 0.31 dB in order for the TM-polarized wave. Second, the working bandwidth with PER > 25 dB and IL < 0.08 dB is 100 nm (1500–1600 nm) for the TE-polarized wave, and that with PER > 20 dB and IL < 0.4 dB is 30 nm (1534–1564 nm) for the TM-polarized wave. Third, the device has a compact structure of 33 μm in length and exhibits definite fabrication tolerance. Overall, the proposed device exhibits ultra-high PER and ultra-low IL, and has a compact size suitable for on-chip use. A comparison shows that present device exhibits advantage in IL and/or size over that based on other LNOI structures or the SOI platform.

Synergistically homogeneous and heterogeneous catalytic strategy enables fast sulfur electrochemical conversion kinetics

Heterostructures composing of two coupling components are of significance for the kinetic improvements of sulfur electrochemistry. However, they encounter a challenge of being incompetent to simultanesouly catalyze the soluble lithium polysulfides via both homogeneous and heterogeneous ways. In this work, a synergistic homogeneous and heterogeneous catalytic process has been implemented in a delicately designed CoTe/Te heterostructure, which is evenly distributed on a densifying carbon framework. The highly conductive CoTe component can efficiently immobilize lithium polysulfides and heterogeneously catalyze their conversion, while the Te component can homogenously catalyze the lithium polysulfides conversion in a way of forming the electrochemically active soluble polytellurosulfide species with intrinsically accelerated redox kinetics. Besides, the densified carbon framework makes a good balance between macropores and mesopores, guaranteeing the electron conduction and alleviating the electrode volume changes. Benefited from these structural merits, the Li-S batteries based on CoTe/Te heterostructure host exhibit superior rate capability (778.6 mAh/g at 4C, 1.4 times higher than sulfur cathodes without heterostructures) and cycle stability (536.7 mAh/g after 1000 cycles at 2C, 1.6 times than sulfur cathodes without heterostructures).

Full spectrum photon management of photonic crystal-based aerogels to achieve the multiscale multiphysics regulations and optimizations of PV-TE/T systems

Multicomponent coupling is an effective way to achieve full-spectrum solar energy utilization. However, conventional multicomponent coupled PV systems are deficient in the rational distribution of full-spectrum sunlight. In this study, a photovoltaic-thermoelectric/thermal (PV-TE/T) system with photonic crystal-based aerogels (PCA) is proposed based on a novel strategy for efficient full-spectrum solar energy utilization. Then, a multiscale multiphysics theoretical model is developed to study the effects of full-spectrum selectivity characteristics of PCA on the performance of the PCA-based PV-TE/T system. Comparative analyses between stand-alone PV system, tandem PV-TE system, normal PV-TE/T system and PCA-based PV-TE/T system are performed. The full-spectrum selectivity characteristics of PCA allows the PCA-based PV-TE/T system to not only increase the maximum achievable photon current density of PV component by 2.39%–3.00%, but also to increase the heat source (light absorption) for TE component by at least 2609.84%. When the concentration increases to 20, the electrical efficiency of the stand-alone PV system is already 0%, and the electrical efficiency of the tandem PV-TE starts to decrease to 27.01%. As for the PCA-based PV-TE/T system, the maximum electrical efficiency of the PCA-based PV-TE/T system is 32.64% at the concentration of 93. Meanwhile, the thermal collector of the PCA-based PV-TE/T system absorbs 6277.5 W/m2 of thermal energy. Therefore, the PCA-based PV-TE/T system not only has a high efficiency of full-spectrum solar energy utilization, but also is applicable to higher concentrations, which offers the system the potential for further cost reductions.

Experimental study on hybridization of a PV–TEG system for electrical performance enhancement using heat exchangers, energy, exergy and economic levelized cost of energy (LCOE) analysis

Abstract The concept of employing thermoelectric generators (TEGs) to recover energy from waste heat has gained popularity, with applications that range from milliwatt to kilowatt levels of output power. In this study, a hybrid photovoltaic panel and thermoelectric generator (HPVTEG) system consisting of an integrated heat exchanger, a commercial polycrystalline silicon photovoltaic (PV) panel and a commercial bismuth telluride TEG was proposed. Here, TE components can be used to cool PV modules, increasing their output power via the Seebeck effect. The main finding is that the hybrid system has a reduced average temperature of 16.01°C. The average power of the stand-alone PV panel is 28.06 W, but that of the HPVTEG system is 32.76 W, which is an increase of 4.7 W. The conversion efficiency and power of the hybrid system increased by 16.7% and 16.4%, respectively, compared with a stand-alone PV panel. The HPVTEG system achieved an average exergy efficiency of 12.79% compared with 10.98% for a stand-alone PV panel. According to the calculation results, the levelized cost of energy (LCOE) of the stand-alone PV panel can range from 0.06741 to 0.10251 US$/kWh depending on how many days it is in operation, while the LCOE of the HPVTEG system can range from 0.06681 to 0.10160 US$/kWh.

A Monolithic Polarization Controller and Tracking Loop for Optical Interconnect Demonstrated on a 90 nm Silicon CMOS-Photonic Platform

We report, to the best of our knowledge, the first monolithically-integrated silicon CMOS-photonic co-designed polarization tracking circuit implemented in a 90 nm CMOS SOI process. The Polarization Splitter and Rotator (PSR) decompose the optical input into TE and TM component and rotate the TM component to TE mode. The directional couplers combine the two TE components from PSR into single optical output. The thermal phase shifters on the optical path maximize the final optical output. A feedback loop implemented with monitoring photodetector, current mode ADC and Finite State Machine (FSM), control the current mode DACs to adjust the current input of thermal phase shifter. The circuit tracks randomized polarization rotation across the Poincaré sphere, maximizes TE-mode optical power, and experimentally achieves a BER of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$10^{-11}$</tex-math></inline-formula> with 10 Gb/s PAM-2 modulation.

Multi-scale multi-physic coupled investigation on the matching and trade-off of conversion and storage of optical, thermal, electrical, and chemical energy in a hybrid system based on a novel full solar spectrum utilization strategy

In order to achieve a reasonable utilization of the full solar spectrum at low-cost, a photovoltaic/thermoelectric/electrolysis (PTE) hybrid system based on a novel full solar spectrum utilization strategy is proposed. The PTE mainly consist of a thermal collector with the spectrally selectively absorption fluid (water), a photovoltaic-thermoelectric (PV–TE) component and a water electrolysis component. Based the structure of the PTE, the full solar spectrum energy can be reasonably and efficiently allocated and utilized. For the complicated coupling physical process in PTE hybrid system, an integrated multi-scale multi-physic theoretical model is developed to optimize and investigate the PTE hybrid system. After the analyses on the multis-scale multi-physic effect of the air insulation layer between the thermal collector and the PV–TE component, it is found that removing air insulation layer leads to the less reflection loss and parasitic absorption, and more the maximum achievable photo current density and the internal heat source for TE component. Moreover, not only does the PV–TE component without the air insulation layer have higher efficiency (27.03%), but the concentration corresponding to the maximum efficiency increase to 31 from 3, which means more output power. By matching the structure and energy between components, the efficiency of the PTE hybrid system can be further improved, while the efficiency and energy storage of the PTE hybrid system can be adjusted according to the demand. Compared to single PV system, the efficiency of the PTE hybrid system has been increased by 15.38% at the concentration of 20, and this difference increases with the concentration. Moreover, the PTE hybrid system can simultaneously generate 200 W/m2 of hydrogen energy at the concentration of 20. In summary, the PTE hybrid system not only offers better performance (generation and storage), but also better integration, providing a guiding idea for the full solar spectrum utilization. Moreover, the multi-scale multi-physic coupled model also provides precise theoretical guidance for the optimization and design.

MODEL DEVELOPMENT AND PERFORMANCE IMPROVEMENT OF A PHOTOVOLTAIC-THERMOELECTRIC SYSTEM BY INTEGRATING AND OPTIMIZING PHASE CHANGE MATERIALS

Integrating phase change materials (PCMs) with concentrated photovoltaic-thermoelectric (PV-TE) systems can effectively control the interface temperature between PV and TE components and improve the full solar-spectrum utilization efficiency. However, since the structure of photovoltaic-phase change material-thermoelectric (PV-PCM-TE) systems is complex and the temperatures among the components are coupled and affect each other, the photo-thermal-electric conversion characteristics under the actual physical properties need to be analyzed by a more detailed model, and the suitable operating conditions for PV-PCM-TE systems remain clear. There is still a lack of the method for improving the system performance. Therefore, a three-dimensional transient model is established herein by combining the Monte Carlo ray-tracing method and finite volume method to simulate the complex energy conversion processes of the PV-PCM-TE system. Based on this, performances of PV-PCM-TE, PV-TE, and PV systems are compared under different operating conditions, and the applicable conditions for PV-PCM-TE systems are analyzed. Then effects of key parameters of the phase change module are investigated. In the end, to further improve the system performance, a partition screening method of PCM is proposed considering the nonuniform solar radiation on photovoltaic surfaces, and the selection and layout area of PCMs are optimized. The results present that the applicable operating conditions are low concentration ratio (&amp;#60; 20) and low heat transfer coefficient (&amp;#60; 20 W&amp;#183;m&lt;sup&gt;-2&lt;/sup&gt;&amp;#183;K&lt;sup&gt;-1&lt;/sup&gt;). In terms of structural parameters, the system power generation is most significantly affected by the width. In terms of PCM physical properties, it is most affected by the PCM density, followed by latent heat. For different concentration ratios, there are different optimal melting points to achieve the highest power generation. The proposed PCM partition screening method can efficaciously control PV-TE interface temperature, and reduce photovoltaic cells' temperature by 47&amp;deg;C. The system efficiency can be increased by 4.8&amp;#37; and 4.2&amp;#37; after the optimization compared with that of the single PV cell and the traditional PV-TE system, respectively.

Enhancement of the conversion efficiency of optical spin-orbit interactions in PT symmetric systems.

The optical spin-orbit interaction (SOI) caused by momentum-dependent Pancharatnam-Berry phase (PB) provides new opportunities in the development of spin-optical devices, but the relatively low conversion efficiency limits its application. Here, through rigorous full-wave analyses on it in a parity-time (PT) symmetric system with thickness less than a wavelength, we find that the conversion efficiency of the SOI can be enhanced in both transmission and reflection in a wide range of incidence angles. When the parameters of the PT symmetric system meet the requirement of coherent perfect absorbers-laser mode, the effective anisotropy between the TM and TE components (e.g., a difference of their Fresnel coefficients) within the beam will be amplified dramatically, which results in significantly enhanced conversion efficiency of SOIs (up to 106). These findings offer an effective way to modulate the SOIs with an ultra-thin PT symmetric system, and may exhibit applications in spin-orbit optical devices.

Selenium and Tellurium Separation: Copper Cementation Evaluation Using Response Surface Methodology

In recent years, high demands for Se and Te in the solar panels and semiconductors industry have encouraged its extraction from primary and secondary sources. However, the two elements’ similar chemical and physical properties make pure element production, Se or Te, arduous. This work is aimed to investigate the significant factors of Se and/or Te recovery in the copper cementation process using the response surface methodology. The test was carried out in two series, for Te and Se, so that H2SO4, CuSO4, Te(or Se) concentration, and temperature are the factors of experimentation. According to response surface methodology (RSM) results for both test series (i. e. Se and Te), 50 g/L H2SO4, 15 g/L Cu, and 35 °C, 3000 mg/L Se (or 750 mg/L Te) was specified for higher Se recovery (97%), and the lowest Te extraction (2%) as an optimum condition, so that could make a suitable separation process. Hence, the cementation test was conducted in the simultaneous presence of Se and Te, so the separation index became 5291. Moreover, the cementation test was carried out in the pregnant leach solution of copper anode slime, and the separation factor was measured to be 606. On the other hand, the thermodynamic evaluation and XRD patterns of the process’s sediments confirm that Se is precipitated as Cu2Se and Cu1.8Se, whereas no Te components are detected in the sediments.

A Matrix Basis Formulation for the Dyadic Green’s Functions of Maxwell’s Equations in Layered Media

A matrix basis formulation is introduced to represent the frequency domain dyadic Green’s functions of Maxwell’s equations in 3-dimensional layered media. The formulation can be used to decompose the Maxwell’s Green’s functions into independent TE and TM components, each satisfying a scalar Helmholtz equation. Moreover, the interface transmission conditions for the electromagnetic fields can be reduced to decoupled conditions for the matrix basis coefficients at interfaces. Numerical results for the electric and magnetic dyadic Green’s functions for a 10-layer medium show the capability of the proposed formulation.

Hybrid TM/TE Cylindrical Leaky Waves: Electromagnetic Radiation at Broadside From Radially Periodic Structures

The nature of broadside radiation from planar, radially periodic structures excited at the center is investigated in this article by considering an annular microstrip antenna operating in the microwave range. This kind of antenna, capable of radiating either a scanned conical pattern or a broadside pencil beam, is typically designed by enforcing that its linearized version supports a single TM leaky mode. However, a single TM cylindrical leaky wave is known to be incapable of radiating a directive broadside beam. To solve the conundrum, a generalized pencil-of-function analysis of the exciting field is performed. It is found that a nonnegligible TE component is present, which exhibits a radial decay different from the TM component but the same complex radial wavenumber. Based on the geometrical symmetries of the structure, an electromagnetic model for the surface currents excited on the annular microstrips is developed and validated by full-wave results for both the currents and the associated radiation patterns. The generality of the adopted approach sheds new light on the nature of the electromagnetic field radiated at broadside by the general class of annular, radially periodic structures, including novel terahertz antennas and plasmonic structures used for achieving extraordinary transmission at optical frequencies.

On enhanced sensing of chiral molecules in optical cavities

The differential response of chiral molecules to incident left- and right-handed circularly polarized light is used for sensing the handedness of molecules. Currently, significant effort is directed toward enhancing weak differential signals from the molecules, with the goal of extending the capabilities of chiral spectrometers to lower molecular concentrations or small analyte volumes. Previously, optical cavities for enhancing vibrational circular dichroism have been introduced. Their enhancements are mediated by helicity-preserving cavity modes which maintain the handedness of light due to their degenerate TE and TM components. In this article, we simplify the design of the cavity and numerically compare it with the previous one using an improved model for the response of chiral molecules. We use parameters of molecular resonances to show that the cavities are capable of bringing the vibrational circular dichroism signal over the detection threshold of typical spectrometers for concentrations that are one to three orders of magnitude smaller than those needed without the cavities, for a fixed analyte volume. Frequency resolutions of current spectrometers result in enhancements of more than one order (two orders) of magnitude for the new (previous) design. With improved frequency resolution, the new design achieves enhancements of three orders of magnitude. We show that the TE/TM degeneracy in perfectly helicity-preserving modes is lifted by factors that are inherent to the cavities. More surprisingly, this degeneracy is also lifted by the molecules themselves due to their lack of electromagnetic duality symmetry, that is, due to the partial change of helicity during the light-molecule interactions.

Bound states in the continuum enable modulation of light intensity in the Faraday configuration.

We demonstrate a novel, to the best of our knowledge, magneto-optical effect that reveals itself in light intensity modulation without polarization rotation in the Faraday configuration. We design a photonic crystal with a magnetized optical cavity that supports bound states in the continuum (BICs), since it simultaneously provides the extended state (continuum) for TM polarization, and the bound (localized) state in the form of a cavity mode for TE-polarized light. Magnetization of the photonic crystal in the Faraday configuration results in efficient polarization conversion and trapping of the acquired TE components of the TM incident light inside the magnetized optical cavity. As a result, a BIC manifests itself as a significant magneto-optical modulation of transmitted light intensity, while its polarization is preserved. Therefore, the proposed structure is promising for magnetic control of light in various applications.

Chiral Plasmons with Twisted Atomic Bilayers.

van der Waals heterostructures of atomically thin layers with rotational misalignments, such as twisted bilayer graphene, feature interesting structural moiré superlattices. Because of the quantum coupling between the twisted atomic layers, light-matter interaction is inherently chiral; as such, they provide a promising platform for chiral plasmons in the extreme nanoscale. However, while the interlayer quantum coupling can be significant, its influence on chiral plasmons still remains elusive. Here we present the general solutions from full Maxwell equations of chiral plasmons in twisted atomic bilayers, with the consideration of interlayer quantum coupling. We find twisted atomic bilayers have a direct correspondence to the chiral metasurface, which simultaneously possesses chiral and magnetic surface conductivities, besides the common electric surface conductivity. In other words, the interlayer quantum coupling in twisted van der Waals heterostructures may facilitate the construction of various (e.g., bi-anisotropic) atomically-thin metasurfaces. Moreover, the chiral surface conductivity, determined by the interlayer quantum coupling, determines the existence of chiral plasmons and leads to a unique phase relationship (i.e., ±π/2 phase difference) between their transverse-electric (TE) and transverse-magnetic (TM) wave components. Importantly, such a unique phase relationship for chiral plasmons can be exploited to construct the missing longitudinal spin of plasmons, besides the common transverse spin of plasmons.

Using the Belinfante momentum to retrieve the polarization state of light inside waveguides

Current day high speed optical communication systems employ photonic circuits using platforms such as silicon photonics. In these systems, the polarization state of light drifts due to effects such as polarization mode dispersion and nonlinear phenomena generated by photonic circuit building blocks. As the complexity, the number, and the variety of these building blocks grows, the demand increases for an in-situ polarization determination strategy. Here, we show that the transfer of the Belinfante momentum to particles in the evanescent field of waveguides depends in a non-trivial way on the polarization state of light within that waveguide. Surprisingly, we find that the maxima and minima of the lateral force are not produced with circularly polarized light, corresponding to the north and south poles of the Poincaré sphere. Instead, the maxima are shifted along the great circle of the sphere due to the phase differences between the scattered TE and TM components of light. This effect allows for an unambiguous reconstruction of the local polarization state of light inside a waveguide. Importantly, this technique depends on interaction with only the evanescent tails of the fields, allowing for a minimally invasive method to probe the polarization within a photonic chip.

Level the Conversion/Alloying Voltage Gap by Grafting the Endogenetic Sb2Te3 Building Block into Layered GeTe to Build Ge2Sb2Te5 for Li-Ion Batteries.

Many research efforts for advanced Li-ion batteries have been made to design new material with large capacity and long cycle life, but little attention has been paid to regulate the voltage platform until now. Although quite attractive for the binary Ge-based chalcogenides, challenge is that a large potential gap as well as incongruous reaction kinetics is typically found between their conversion step (>1.6 V) and alloying region (<0.4 V). Herein, we propose an endogenetic structural design by grafting Sb2Te3 building block into layered GeTe to establish a ternary Ge2Sb2Te5 compound, which can effectively level such a big potential gap. Turning from semiconductive GeTe into metallic conductive Ge2Sb2Te5, the reaction kinetics can be enhanced. The LixTe formation step in Ge2Sb2Te5 is found declined to 1.30 V, and the enlistment of Sb (∼0.78 V) bridges the conversion and alloying plateau; thus, the incongruous reaction kinetics and large potential gap between the conversion-alloying step can be alleviated. Furthermore, there is a spatially confined and synergistic effect among Te, Sb, and Ge components, conducting the LixTe and LixGe processes in a more harmonious and gentle way. Therefore, Ge2Sb2Te5 exhibites much enhanced cyclability and rate performance, with 546 mAh/g remained at 2000 mA/g. This unique design strategy can be leveraged to manipulate the voltage profile of other compounds.

Approach of realizing arbitrary wavefront manipulation with continuous meander line structures

In the paper, we systematically present the approach of realizing arbitrary wavefront manipulation with continuous meander line structures that can send the outgoing light with the opposite polarization in respect to the incident light into desired directions. The manipulation behavior is found to be wavelength-dependent, analogous to the traditional grating. Propagation characteristic and filed analysis are used to understand the generation of the polarization conversed outgoing light. The results suggest that the surface mode of TM component mainly governs at long wavelength and the oscillating mode of TE component is dominant at short wavelength, resulting in a broad operation region. The backward process, i.e., deriving a special function based on the given irradiation pattern, verifies the generation of the approach. The finding gives an alternative to realize the wavefront manipulation of transmitted light with a thin metal device and an insight into the traditional meander line structure.

Study of G-Protein Coupled Receptor Signaling in Membrane Environment by Plasmon Waveguide Resonance.

Here we describe an experimental technique, termed plasmon waveguide resonance (PWR) spectroscopy that enables the characterization of molecular interactions occurring at the level of anisotropic thin films as lipid membranes and therein inserted or interacting molecules. PWR allows one to characterize such molecular interactions at different levels: (1) acquire binding curves and calculate dissociation constants; (2) obtain kinetic information; (3) obtain information about associated anisotropy changes and changes in membrane thickness; (4) obtain insight about lateral homogeneity (formation of domains). Points 1, 2, and 4 can be directly obtained from the data. Point 3 requires spectral fitting procedures so that the different optical parameters characterizing thin films as proteolipid membranes, namely refractive index and extinction coefficient for both p- (TM component of light that is parallel to the incident light) and s- (TE component of light that is perpendicular to the incident light) polarizations and thickness, can be determined. When applied to membrane proteins as the G-protein coupled receptor (GPCR) family, both ligand-induced conformational changes of the receptor can be followed as well as interactions with effectors (e.g., G-proteins). Additionally, by either altering the lipid composition in cellular membranes or specifically controlling its composition in the case of lipid model membranes with reconstituted proteins, the role of the lipid environment in receptor activation and signaling can be determined. Additionally, the eventual partition of receptors in different lipid microdomains (e.g., lipid rafts) can be followed. Such information can be obtained ex cellulo with mammalian cell membrane fragments expressing the protein of interest and/or in vitro with lipid model systems where the protein under investigation has been reconstituted. Moreover, PWR can also be applied to directly follow the reconstitution of membrane proteins in lipid model membranes. The measurements are performed directly (no labeling of molecular partners), in real time and with very high sensitivity. Here we will discuss different aspects of GPCR activation and signaling where PWR brought important information in parallel with other approaches. The utility of PWR is not limited to GPCRs but can be applied to any membrane protein. PWR is also an excellent tool to characterize the interaction of membrane active molecules (as cell penetrating, antimicrobial, viral and amyloid peptides) with lipids. A brief section is dedicated to such applications, with particular emphasis on amyloid peptides. To finalize, as PWR is a homemade technology, ongoing instrument developments aiming at breaking current experimental limitations are briefly discussed, namely, the coupling of PWR with electrochemical measurements and the expansion of measurements from the visible to the infrared region.