Explore the vast range of titles available.

This interdisciplinary research is focused on constructing and demonstrating enhanced-reach polarization optical time-domain reflectometer (POTDR) for monitoring single-mode fibre optical communication lines. An optical signal state of polarization measurements enables several new possibilities for real-time monitoring solutions in fibre optics. However, there is no commercial equipment available to determine the location in fibre optical cable where the light polarization state changes. The authors present a monitoring technique of an optical signal state of polarization based on reflected signal time-amplitude analysis with improved operation parameters, namely, timing resolution (2 to 3 ps RMS) and amplitude measurement resolution of nanosecond scale pulses (8 to 10 bits) for monitoring of fibre optical communication lines. Additionally, the demonstrated POTDR provides a considerable optical fibre line measurement reach of up to 40 km.

Oil spills lead to catastrophic problems. In most oil spill cases, the spatial and temporal intractability of the detriment cannot be neglected, and problems related to economic, social and environmental factors constantly appear for a long time. Remote sensing has been widely used as a powerful means to conduct oil spill detection. Optical polarization remote sensing, thriving in recent years, shows a novel potential for oil spill detection. This paper provides a demonstration of the use of open-source POLDER/PARASOL polarization time-series data to detect oil spill. The Deepwater Horizon oil spill, one of the largest oil spill disasters, is utilized to explore the potential of optical polarization remote sensing for oil spill detection. A total of 24 feature combinations are organized to quantitatively study the positive effect of adding polarization information and the appropriate way to describe polarization characteristics. Random forest classifier models are trained with different combinations, and the results are assessed by 10-fold cross-validation. The improvement from adding polarization characteristics is remarkable ((average) accuracy: +0.51%; recall: +2.83%; precision: +3.49%; F1 score: +3.01%, (maximum) accuracy: +0.80%; recall: +5.09%; precision: +6.92%; F1 score: +4.72%), and coupling between the degree of polarization and the phase angle of polarization provides the best description of polarization information. This study confirms the potential of optical polarization remote sensing for oil spill detection, and some detailed problems related to model establishment and polarization feature characterization are discussed for the further application of polarization information.

We demonstrate 60 GHz separation optical two-tone signal generation at arbitrary C-band wavelengths without involving complicated optical wavelength filtering. By utilizing a polarizer, the selective suppression of undesired low-order optical sidebands has been proven and optimized based on model analysis. By utilizing this scheme in conjunction with the optimized parameters, more than 20 dB of suppression of undesired optical sidebands have been successfully achieved over a 40 nm wavelength range. This scheme allows us to generate optical two-tone signals at the desired wavelength.

Tellurium (Te), as one of the chalcogens, is an emerging single-element non-layered p-type semiconductor material. Two-dimensional (2D) Te has shown great application potential in environmental stability, piezoelectric effect, high carrier mobility, and other fields. However, 2D Te is much less known compared to other traditional 2D materials. Herein, 2D Te nanosheets with the thickness of 20–40 nm and 10–20 nm growing under different temperatures and pressure were manufactured successfully by the physical vapor deposition (PVD) method. And the polarization-dependent optical absorption through the polarization-dependent coupling structure (Te/Mica sandwich structure) on a quartz prism was investigated. The results show that the 2D Te nanosheets have intense absorption of TE waves in the visible band. This work provides an experimental basis for the preparation of 2D Te in the future and points the way for its application in optical polarization devices.

Marine observation is a worldwide challenge, which implicates for a large number of social, economic and scientific problems. Satellite remote sensing provides incredible convenience for marine observation, and remote sensing techniques with different wavelength range have been developed for scientific use related to oceanography, among of which optical polarization remote sensing is a rapidly growing field in the recent decade. Although some attempts have been made about utilizing optical polarization technique for marine observation, the potential of optical polarization remote sensing is far from being fully released and the current skills of optical polarization image processing are too coarse to extract deep information from raw images. In our experiment at Nanchang river park, three application scenarios are selected to illustrate advances in optical polarization remote sensing for marine observation, specifically including sun-glint observation, phytoplankton monitoring and coastal topography mapping. A baseline for optical polarization image processing is established for marine observation and the advantages of optical polarization technique are assessed qualitatively and quantitatively, proving that: For marine observation, optical polarization remote sensing can reduce overexposure rate, enhance dynamic range, depict subsurface phytoplankton and map coastal topography.

Polarization transformation is at the foundation of modern applications in photonics and quantum optics. Notwithstanding their applicative interests, basic theoretical and experimental efforts are still needed to exploit the full potential of polarization optics. Here, we reveal that the coherent superposition of two non-orthogonal eigen-states of Jones matrix can improve drastically the efficiency of arbitrary polarization transformation with respect to classical orthogonal polarization optics. By exploiting metasurface with stacking and twisted configuration, we have implemented a powerful configuration, termed “non-orthogonal metasurfaces”, and have experimentally demonstrated arbitrary input-output polarization modulation reaching nearly 100% transmission efficiency in a broadband and angle-insensitive manner. Additionally, we have proposed a routing methodology to project independent phase holograms with quadruplex circular polarization components. Our results outline a powerful paradigm to achieve extremely efficient polarization optics, and polarization multiplexing for communication and information encryption at microwave and optical frequencies. The authors showcase a general method to engineer arbitrary polarization transformation with efficiency reaching nearly unity, taking advantage of non-orthogonal eigen-formalism of Jones matrix to circumvent the limitation of conventional polarization optics.

A sensitive laser registration of weak polarization-optical responses was used for the investigations of dilute magnetic nanofluids. Criteria for weak and strong signals for probing of sample by laser radiation with deep modulation of polarization were considered. The magneto-optical responses of a kerosene-based fluid with magnetite nanoparticles were investigated over a wide (five orders of magnitude) range of concentrations. Weak polarization responses for this nanofluid were observed at record low volume concentrations of nanoparticles up to 10-7.

Polarization plays a key role in science; hence its versatile manipulation is crucial. Existing polarization optics, however, can only manipulate polarization in a single transverse plane. Here we demonstrate a new class of polarizers and wave plates—based on metasurfaces—that can impart an arbitrarily chosen polarization response along the propagation direction, regardless of the incident polarization. The underlying mechanism relies on transforming an incident waveform into an ensemble of pencil-like beams with different polarization states that beat along the optical axis thereby changing the resulting polarization at will, locally, as light propagates. Remarkably, using form-birefringent metasurfaces in combination with matrix-based holography enables the desired propagation-dependent polarization response to be enacted without a priori knowledge of the incident polarization—a behaviour that would require three polarization-sensitive holograms if implemented otherwise. Our work expands the use of polarization in the design of multifunctional metasurfaces and may find application in tunable structured light, optically switchable devices and versatile light–matter interactions.Using a metasurface that allows shaping of the polarization state of a light beam independently at each point of space along its propagation direction, longitudinally variable polarization optical components are demonstrated, inspiring new directions in structured light, polarization-switchable devices and light–matter interaction.

A theoretical model of the formation of the stress-strain state in elastomers under the action of a concentrated load is considered. Experimental studies were carried out using the polarization-optical method. As a sample, transparent L-83 polyurethane with physical and mechanical characteristics corresponding to typical rubbers was used. It is shown that the stress-strain state of the surface layer calculated as a result of the theoretical solution of the mathematical model coincides with the experimental data. When loading, zones of compressive and tensile stresses are created. The magnitude of the tensile stress determines the likelihood of surface destruction (tearing). Simulation of an oblique impact confirmed the qualitative picture of the stress-strain state in elastomers under the action of a concentrated load. A theoretical study made it possible to establish that the potential energy of deformation is distributed over the depth of the surface layer in inverse proportion to the square of the distance from the point of application of the force, i.e., the point of contact of the solid particle with the surface of the elastomer. This makes it possible to mathematically calculate the level and distribution of energy dissipation in the wear volume of the surface layer. Theoretical and practical studies have shown that in the practical use of elastomer linings, it is recommended to install them at an angle close to 90° to the direction of solids flow.

Optical polarization provides important clues to the magnetic field in blazar jets. It is easy to find noteworthy patterns in the time-series data of the polarization degree (PD) and position angle (PA). On the other hand, we need to see the trajectory of the object in the Stokes Q U plane when the object has multiple polarized components. In this case, ironically, the more data we have, the more difficult it is to gain any knowledge from it. Here, we introduce TimeTubes, a new visualization scheme to explore the time-series data of polarization observed in blazars. In TimeTubes, the data is represented by tubes in 3D (Q, U, and time) space. The measurement errors of Q and U, color, and total flux of objects are expressed as the size, color, and brightness of the tubes. As a result, TimeTubes allows us to see the behavior of six variables in one view. We used TimeTubes for our data taken by the Kanata telescope between 2008 and 2014. We found that this tool facilitates the recognition of the patterns in blazar variations; for example, favored PA of flares and PA rotations associated with a series of flares.