Ideal Polarization Research Articles

Long-term Monitoring of Oxygen Consumption Rates in Highly Differentiated and Polarized Retinal Pigment Epithelial Cultures.

Mitochondrial metabolism is critical for the normal function of the retinal pigment epithelium (RPE), a monolayer of cells in the retina important for photoreceptor survival. RPE mitochondrial dysfunction is a hallmark of age-related macular degeneration (AMD), the leading cause of irreversible blindness in the developed world, and proliferative vitreoretinopathy (PVR), a blinding complication of retinal detachments. RPE degenerative conditions have been well-modeled by RPE culture systems that are highly differentiated and polarized to mimic in vivo RPE. However, monitoring oxygen consumption rates (OCR), a proxy for mitochondrial function, has been difficult in such culture systems because the conditions that promote ideal RPE polarization and differentiation do not allow for easy OCR measurements. Here, we introduce a novel system, Resipher, to monitor OCR for weeks at a time in well-differentiated RPE cultures while maintaining the RPE on optimal growth substrates and physiologic culture media in a standard cell culture incubator. This system calculates OCR by measuring the oxygen concentration gradient present in the media above cells. We discuss the advantages of this system over other methods for detecting OCR and how to set up the system for measuring OCR in RPE cultures. We cover key tips and tricks for using the system, caution about interpreting the data, and guidelines for troubleshooting unexpected results. We also provide an online calculator for extrapolating the level of hypoxia, normoxia, or hyperoxia RPE cultures experience based on the oxygen gradient in the media above cells detected by the system. Finally, we review two applications of the system, measuring the metabolic state of RPE cells in a PVR model and understanding how the RPE metabolically adapts to hypoxia. We anticipate that the use of this system on highly polarized and differentiated RPE cultures will enhance our understanding of RPE mitochondrial metabolism both under physiologic and disease states.

All-optical polarization scrambler based on polarization beam splitting with an amplified fiber ring

Optical-fiber-based polarization scramblers can reduce the impact of polarization sensitive performance of various optical fiber systems. Here, we propose a simple and efficient polarization scrambler based on an all-optical Mach-Zehnder structure by combining a polarization beam splitter and an amplified fiber ring. To totally decoherence one polarization split beam, a fiber ring together with an amplifier is incorporated. The ratio of two orthogonal beams can be controlled by varying the amplification factor, and we observe different evolution trajectories of the output state of polarizations on the Poincaré sphere. When the amplification factor exceeds a certain threshold, the scrambler system exhibits nearly ideal polarization scrambling behavior. A commercial single wavelength laser with a linewidth of 3 MHz is utilized to characterize the scrambling performance. We found that when the sampling rate is 1.6 MSa/s, a scrambling speed up to 2000krad/s can be obtained for the average degree of polarization being less than 0.1. We also exploit these random polarization fluctuations to generate random binary numbers, indicating that the proposed technique is a good candidate for a random bit generator.

Rotation of reference frame dependent polarimetric variables for equidistant fisheye lens projections.

The effect of a linear polarizer is conventionally well defined when viewed along the axis normal to its face. However, even for ideal linear polarizers, the non-normal viewing geometries attainable with wide-angle lenses require further considerations. A method to describe the polarization state of light passed through a linear polarizer and observed with an equidistant fisheye lens is described.

Investigation of the surface mechanical properties of functionalized single-walled carbon nanotube (SWCNT) reinforced PDMS nanocomposites using nanoindentation analysis.

Functionalizing single-walled carbon nanotubes (SWCNT) with different chemical functional groups directly enhances their chemical adhesion and dispersion in viscous polymeric resins such as polydimethylsiloxane (PDMS). Nevertheless, the ideal surface polarity (hydrophilic or hydrophobic) for SWCNT to foster stronger chemical bonding with PDMS remains uncertain. This investigation delves into the impact of enhanced SWCNT dispersion within PDMS on the surface mechanical characteristics of this flexible composite system. We use carboxylic acid-functionalized SWCNT (COOH-SWCNT) and silane-functionalized SWCNT (sily-SWCNT), recognized for their hydrophilic and hydrophobic surface polarities, respectively, as reinforcing agents at ultra-low weight percentage loadings: 0.05 wt%, 0.5 wt%, and 1 wt%. We perform quasi-static nanoindentation analysis employing a Berkovich tip to probe the localized mechanical behavior of PDMS-SWCNT films at an indentation depth of 1 μm. Plastic deformation within the samples, denoted as plastic work (Wp), as well as the elastic modulus (E), hardness (H), and contact stiffness (Sc) of the composites are examined from the force-displacement curves to elucidate the enhancement in the surface mechanical attributes of the composite films.

Connecting the microscopic depolarizing origin of samples with macroscopic measures of the Indices of Polarimetric Purity

In this work we show how a specific set of three depolarizing observables, the Indices of Polarimetric Purity (IPP), P1, P2 and P3, are ideal metrics to study the depolarization characteristic of media. We simulate different depolarizing scenarios, based on different depolarizing origins, and we study the corresponding IPP values. The simulations are based on the incoherent addition of multiple elemental polarizing elements, as ideal polarizers and/or retarders with different specific characteristics (orientation, retardance, transmittance, etc.). Further depolarizing scenarios are also studied by including the effect of ideal depolarizers. We show for the first time how by analyzing depolarizing systems through IPP we unravel two different depolarizing origins: isotropic and anisotropic depolarization, with meaningful physical interpretation. The former, isotropic depolarization is related to pure scattering processes, and mainly connected with P3 observable. The later, anisotropic depolarization is originated by microscopic constituent elements showing polarimetric anisotropy (dichroic and/or birefringent elements with different characteristics) and anisotropic scattering produced by these elements, and mainly described by P1 and P2 observables. Both effects can be simultaneously observed in real samples and give us information of the processes that give rise to depolarization in light-matter interactions. The simulated results are experimentally validated by analyzing the depolarizing behavior, in terms of IPP, of diverse real samples with easy physical interpretation, and direct connection with simulations. The present study could be of interest in multiple scenarios, to further understand the depolarizing response of samples, and it can be of special interest for the study of biological tissues and pathologies, as they present important depolarizing behavior.

Development of a terahertz metamaterial polarization converter with multiple tuning modes based on graphene and vanadium dioxide

A dynamically tunable terahertz metamaterial polarization converter is proposed. By manipulating the Fermi level of graphene and the conductivity of vanadium dioxide (VO2) flexibly, multiple tuning modes for polarization conversion performance are realized. First, while graphene is in the metallic or insulating state, we can achieve an ideal broadband reflective or an ideal broadband transmissive polarization converter respectively. By manipulating the conductivity of VO2, a modulation depth of 80 % for intensity of the reflected polarization conversion rate (PCRr) and that of 70 % for bandwidth of the transmissive polarization conversion rate (PCRt) can be achieved. Then, while VO2 is in the insulating state, we obtain another broadband transmissive polarization converter. Similarly, we can achieve PCRt intensity modulation by manipulating the Fermi level of graphene. While VO2 is in the metallic state, the device can switch from a broadband polarization converter to a narrow one as the Fermi level of graphene increases. Finally, by manipulating graphene and VO2 simultaneously, the central frequency modulation of PCRt can be obtained with the bandwidth keeping unchanged. Compared with the ones reported recently, our device has some advantages on tuning mode, relative bandwidth, and polarization conversion performance.

Binary geometric-phase holograms.

Diffractive optics elements have exhibited many novel characteristics through various methods of employing Pancharatnam-Berry, or geometric, phase. One geometric-phase hologram (GPH) subset, consisting of a π-difference binary sampling, shows polarization-independent properties that are not present in the continuous GPH and the dynamic-phase binary analog. Here, we investigate the binary geometric-phase holograms (bin-GPHs) realized with anisotropic liquid crystal (LC) polymers. First, the optical properties of the ideal binary polarization grating are derived and simulated showing 81% cumulative first-order efficiency, polarization-independent diffraction when applying a π-switching scheme, innate odd (m = 2k + 1) diffractive orders, and variable polarization output. After, experimental results of two key bin-GPH elements, the binary polarization grating (Λ = 30μm) and binary geometric-phase lens (f/100), with π-offset regions and a 0.5μm transition pixel are presented. We found that the fabricated non-ideal bin-GPHs exhibit near-maximum theoretical polarization-insensitive diffraction efficiency and tunable polarization outputs. The simple, and scalable, fabrication of the anisotropic bin-GPH provides the potential for implementation within the next-generation near-eye displays for polarization-invariant beam-steering and waveguides.

Thermal-stress-induced birefringence management of complex laser systems by means of polarimetry

The novel method of the thermally-induced polarization changes driven power losses (TIPCL) analysis in the complex laser systems has been developed. The measurement has been tested on the amplifier chain of the 100 J / 10 Hz laser system ‘Bivoj’ operated at HiLASE Centre. By the usage of the measured non-uniform Mueller matrix of the amplifier chain, the optimization of the ideal input and output polarization state has been calculated numerically. The results of the optimization have been applied to the laser system, thus reducing the TIPCL from originally observed more than 33% to 7.9% for CW beam and to 9% for pulsed laser beam, respectively. To the best of our knowledge, this result represents the most efficient TIPCL suppression method for complex laser systems so far. The method also allows the definition of the ideal fully polarized non-uniform pre-compensation of input beam consequently suffering from zero TIPCL.

Optics of helical periodical media with giant magneto-optical activity

The features of the optical properties of cholesteric liquid crystals (CLC) with enormous magneto-optical activity were investigated. It is shown that the system under consideration has the property of nonreciprocal reflection / transmission, absorption and light energy localization. It was shown that this system can work as an almost ideal tunable polarization plane rotator. An external magnetic field leads to a change (tune) of the localized light energy in the CLC layer over a wide range and this property can also find important practical applications.

Spontaneous valley polarization in two-dimensional organometallic lattices

2D ferrovalley materials that exhibit spontaneous valley polarization are both fundamentally intriguing and practically appealing to be used in valleytronic devices. Usually, the research on 2D ferrovalley materials is mainly focused on inorganic systems, severely suffering from in-plane magnetization. Here, we alternatively show by kp model analysis and high-throughput first-principles calculations that ideal spontaneous valley polarization is present in 2D organometallic lattice. We explore the design principle for organic 2D ferrovalley materials composed of (quasi-)planer molecules and transition-metal atoms in hexagonal lattice, and identify twelve promising candidates. These systems have a ferromagnetic or antiferromagnetic semiconducting state, and importantly they exhibit robust out-of-plane magnetization. The interplay between spin and valley, together with strong spin-orbit coupling of transition-metal atoms, guarantee the spontaneous valley polarization in these systems, facilitating the anomalous valley Hall effect. Our findings significantly broaden the scientific and technological impact of ferrovalley physics.

On the causes of non-linearity of galvanostatic charge curves of electrical double layer capacitors

In the analysis of electrochemical behavior of electrical double layer capacitors (EDLC), it is generally accepted that the linear form of chronopotentiograms testifies to the ideal polarization of the electrode and any deviations from the linearity are interpreted most often as the appearance of Faraday processes on the electrode surface. However, studies on electrochemical behavior of supercapacitors based on carbon materials should take into account the surface nonequipotentiality caused by the porosity of electrode materials, which complicates the formation of electrical double layer (EDL). The influence of this factor is clearly demonstrated by the results obtained in this work with the use of micro- and mesoporous carbon materials of different origin. To accurately estimate the dependence of linearity of chronopotentiograms on porosity of the electrode material, low current densities were used (from 0.008 to 0.08 mA/cm2). A comparison of charge curves at different charge currents showed that the time dependence of voltage changes considerably with an increase in the current load. A formal comparison of chronopotentiograms linearity obtained at different current loads was made using dimensionless coordinates on the time axis, which were expressed as a percentage of the overall polarization time. Only the charging branch of chronopotentiogram was analyzed here because the anodic branch had similar formal characteristics.

Bee-shaped host with ideal polarity and energy levels for high-efficiency blue and white fluorescent organic light-emitting diodes

An ideal host for blue emitters with thermally activated delayed fluorescence (TADF) should bear a moderate polarity to relax charge transfer (CT) states of dopant for a reduced singlet-triplet energy gap (ΔEST) while utter-mostly keeping blue emission, a high triplet energy to confine exciton, and a small ΔEST for feasible charge injection. However, it is rather challenging to simultaneously fulfill all those requirements as the strong CT characteristic necessary for a small ΔEST usually enlarge polarity and lower energy levels. Here, a symmetrical ortho-linked diphenylphosphine oxide (DPO)/carbazole derivative is developed, of which the configuration resembles the bee with carbazoles as front wings, phenyl rings on DPO as back wings, hooked together by π-π interaction. This motif features a short distance of charges for a moderate polarity of 3.45 D, a twisted non-conjugation structure for a small ΔEST of 0.24 eV with a high triplet of 2.98 eV and multiple intermolecular interactions for enhanced charge transport. The corresponding blue TADF device realizes a compromise between efficiency and colors with a maximum external quantum efficiency (EQEmax) of 35.7% and a CIEy of 0.20. Furthermore, a full-TADF white device with this host realizes a EQEmax of 26.1%, representing the state-of-the-art performance.

Optimization of High-Speed Electrolytic Plating of Copper Pillar to Achieve a Flat Top Morphology and Height Uniformity

Abstract Cu plating bath for high-speed electrodeposition of Cu pillar was designed in consideration of a flat top morphology of pillar and a pillar height uniformity. An ideal polarization curve was assumed for the flat top morphology. To obtain the ideal polarization curve, an effect of organic additive concentration and solution agitation on the polarization curve were investigated. The basic bath components were optimized considering a Wagner number to improve the pillar height uniformity. To confirm the pillar top morphology and the pillar height uniformity, a 300-mm diameter wafer was plated with Cu at 20 A/dm2. As a result, improved pillar top morphology and pillar height uniformity were obtained. The optimized plating bath was applied to the plating of a large-size panel of 415 × 510 mm.

Method of full polarization control of microwave fields in a scalable transparent structure for spin manipulation

The application of transparent conducting oxides in electronic devices like solar cells or displays is common. By transferring this technology to quantum sensing and computing in the form of microwave conductors, it is possible to benefit from the advantages of these materials. By using indium tin oxide (ITO), it is demonstrated that at an arbitrary position below the conductor, an arbitrary elliptical microwave polarization can be produced by two independent sources. This is independent of the geometry and size of the ITO, whereby a non-resonant microwave approach can be chosen. Using single nitrogen vacancy (NV) centers in diamond in combination with a cross-like ITO structure, each NV center can be addressed with an ideal (clockwise or anticlockwise) microwave polarization. By optimizing the coupling of the microwave field to the NV centers and minimizing the conductor size, the creation of smaller devices compared to common approaches is possible.

A tunable single-longitudinal-mode wedge Nd:YVO4 laser with a YVO4 wave-plate

We report a tunable single-longitudinal-mode laser based on a wedged Nd:YVO4 gain medium and a YVO4 wave-plate. By taking advantage of the natural birefringence of YVO4 and adopting different cutting methods, a wedged Nd:YVO4 crystal acts as an ideal polarizer by the alignment sensitivity of the optical resonator, and a YVO4 crystal is used as a wave-plate by adjusting the temperature. A theoretical analysis of the single- longitudinal-mode operation of such a laser configuration is presented. The wavelength can be continuously tuned by the temperature at approximately 0.025 nm/°C, and the temperature tuning ranges of single-longitudinal-mode operation at pump powers of 1 W and 2 W are from 12 °C to 30 °C and from 11 °C to 26 °C, respectively. The maximum single-longitudinal-mode output power with linear polarization is 762 mW at a pump power of 2.2 W with a slope efficiency of 40%.

Optimization of High-Speed Electrolytic Plating of Copper Pillar to Achieve a Flat Top Morphology and Height Uniformity

Abstract Cu plating bath for high-speed electrodeposition of Cu pillar was designed in consideration of a flat top morphology of pillar and a pillar height uniformity. An ideal polarization curve was assumed for the flat top morphology. To obtain the ideal polarization curve, an effect of organic additive concentration and solution agitation on the polarization curve were investigated. The basic bath components were optimized considering a Wagner number to improve pillar height uniformity. To confirm the pillar top morphology and the pillar height uniformity, a 300 mm diameter wafer was plated with Cu at 20 A/dm2. As a result, improved pillar top morphology and pillar height uniformity were obtained. The optimized plating bath was applied to the plating of large-size panel of 415 × 510 mm.

Polarization imaging model considering the non-ideality of polarizers.

Common polarization imaging models are mostly based on an ideal polarizer assumption. This paper proposes a polarization imaging non-ideal model considering the non-ideality of polarizers. The corresponding correction formulas for degree of linear polarization (DoLP) and angle of polarization are also provided. Experiments on linearly polarized light and partially polarized light reflected by a glass plate suggest that when the extinction ratio of polarizers is 100:1, the DoLP relative error of linearly polarized light with the non-ideal model is reduced by 1.87% compared to that with the ideal model; the DoLP relative error of partially polarized light with the non-ideal model is reduced by 1.69% compared to that with the ideal model. Application of the non-ideal model can effectively improve the precision of polarization measurement. In particular, this improvement is more obvious with a low-extinction-ratio (less than 100:1) analyzer.

Generating high-performance polarization measurements with low-performance polarizers: demonstration with a microgrid polarization camera

Microgrid polarization cameras have historically experienced lower performance than is typical for monolithic polarization systems. Specifically, their polarizer elements have had a lower extinction ratio and a larger orientation error. We show how to use the calibrated parameters of a nonideal polarizer to modify the polarization measurement model, effectively allowing one to generate high-performance measurements from low-performance elements. We demonstrate the effectiveness of this approach on a commercial polarization camera and estimate the signal-to-noise ratio penalty for using nonideal polarizers in this camera as being 1.25 × versus a system using ideal polarizers.

High frequency mode generation by toroidal Alfvén eigenmodes

Nonlinear generation of high frequency modes (HFMs) by the toroidal Alfvén eigenmode (TAE) observed in the HL-2A tokamak is analyzed using nonlinear gyrokinetic theory. It is found that the HFM can be dominated by |nq−m|=1 perturbations with predominantly ideal magnetohydrodynamic polarization if the two primary TAEs are copropagating, while the HFM can be characterized by nq − m = 0 electrostatic perturbations if the two primary TAEs are counter-propagating. Here, n and m are the toroidal and poloidal mode numbers, respectively, and q is the safety factor. The nonlinear process is sensitive to the equilibrium magnetic geometry of the device.

Twin-core sunflower-type photonic quasicrystal fibers incorporated gold, silver, and copper microwire: an ultrashort and broad bandwidth polarization splitter

Polarization splitters are beneficial in the field of passive optical devices which are principally used in the coherent optical communication systems. An ideal polarization splitter must possess an efficient coupling with significant optical bandwidth. Hence, we proposed a novel metal-filled polarization splitter based on twin-core sunflower-type photonic quasicrystal fiber (PQF). The characteristics of the proposed splitter such as coupling length, extinction ratio, and available optical bandwidth were investigated by using the commercially available software, COMSOL Multiphysics. These aforementioned characteristics were determined by optimizing the geometrical parameters of proposed PQF—first by using gold-filled PQF (AuPQF). With optimized geometrical parameters, the splitter achieved an ultra-short coupling length of 132 µm and an ultra-broad bandwidth of 301 nm (wavelength range 1.36–1.68 µm) with an extinction ratio below than − 20 dB which comprised E + S+C + L+U band. Secondly, a comparative study to use silver- and copper-filled PQF (AgPQF and CuPQF) was explored. Both AgPQF and CuPQF retained a short length with adequate bandwidth and a significant extinction ratio below than − 20 dB. The AgPQF has a coupling length of 137 µm with a bandwidth of 136 nm which operated at 1.44 µm wavelength, while CuPQF with 134 µm lengths with a bandwidth of 149 nm and operated at 1.50 µm wavelengths.