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"polarization"
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35 Core Polarization-Maintaining Multi-core Fiber for High Power Operation
This work presents a novel rod-type 35 core multi-core fiber design that is capable of overcoming the inherent lack of polarization maintenance in such structures. A polarization extinction ratio of 10.5dB is achieved.
Journal Article
FAST Observations of FRB 20220912A: Burst Properties and Polarization Characteristics
We report the observations of FRB 20220912A using the Five-hundred-meter Aperture Spherical radio Telescope. We conducted 17 observations totaling 8.67 hr and detected a total of 1076 bursts with an event rate up to 390 hr−1. The cumulative energy distribution can be well described using a broken power-law function with the lower- and higher-energy slopes of −0.38 ± 0.02 and −2.07 ± 0.07, respectively. We also report the L-band (1–1.5 GHz) spectral index of the synthetic spectrum of FRB 20220912A bursts, which is −2.6 ± 0.21. The average rotation measure value of the bursts from FRB 20220912A is −0.08 ± 5.39 rad m−2, close to 0 rad m−2 and was relatively stable over 2 months. Most bursts have nearly 100% linear polarization. About 45% of the bursts have circular polarization with Signal-to-Noise ratio > 3, and the highest circular polarization degree can reach 70%. Our observations suggest that FRB 20220912A is located in a relatively clean local environment with complex circular polarization characteristics. These various behaviors imply that the mechanism of circular polarization of FRBs likely originates from an intrinsic radiation mechanism, such as coherent curvature radiation or inverse Compton scattering inside the magnetosphere of the FRB engine source (e.g., a magnetar).
Journal Article
Reaching the efficiency limit of arbitrary polarization transformation with non-orthogonal metasurfaces
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.
Journal Article
I'm right and you're an idiot : the toxic state of public discourse and how to clean it up
\"The environment can be polluted, as can public discourse. I'm Right and You're an Idiot examines the state of today's public square, showing how polarized conversations discourage people from taking action on issues such as climate change, and demonstrating how we can clear the air and become more powerful and effective communicators.\"-- Provided by publisher.
Book
A modified dumbbell-shaped highly efficient broadband multifunctional polarizer for X and Ku band applications
A novel metasurface offering polarization conversion characteristic in five bands is studied and developed in this paper. To provide the anisotropic feature to the structure, a diagonally placed tapered rod is combined with two semicircular stubs. Due to the controlling ability to convert horizontal to vertical polarization and vice versa, and linear to circular polarization (CP), it serves as a multifunctional polarization converter. Simulation results suggest that the proposed polarizer functions as cross polarizer over 4.74−5.12 and 9.12−13.48 GHz. Additionally, it exhibits a distinct type of rotational sense across 4.24−4.68, 5.24−8.64, and 13.72–15.14 GHz in its linear to CP conversion behavior. The axial ratio of the polarizer is well below 3 dB throughout overall CP bands due to the minimum tolerance level in reflection phases with respect to acceptable limits. Moreover, it is noticed that the sense of CP is left-handed in the first band while right-handed in the remaining two bands. Thus, the suggested polarizer has potential to be integrated with antennas for satellite, defense, industry applications for getting the desired type of polarization in the distinguished bands.
Journal Article
Outraged : why we fight about morality and politics and how to find common ground
\"In this insightful tour of the moral mind, Gray provides a groundbreaking new framework for our moral foundations that rewrites our understanding of where moral judgments come from, and how we can overcome the feelings of outrage that so often divide us\"-- Provided by publisher.
BOOK
Separation of enantiomers by their enantiospecific interaction with achiral magnetic substrates
There are two common ways to distinguish mirror-image molecules, or enantiomers. The first relies on their distinct interactions with circularly polarized light, the second on their interactions with a pure enantiomer of some other molecule. Now Banerjee-Ghosh et al. report a conceptually different approach to chiral resolution. Experiments showed that, depending on the direction of magnetization, chiral oligopeptides, oligonucleotides, and amino acids have enantiospecific differences in initial adsorption rates on ferromagnetic surfaces. This effect is attributed to enantiospecific induced spin polarization. Science , this issue p. 1331 Spin polarization of chiral molecules enhances the initial adsorption rate of one enantiomer onto a ferromagnetic substrate. It is commonly assumed that recognition and discrimination of chirality, both in nature and in artificial systems, depend solely on spatial effects. However, recent studies have suggested that charge redistribution in chiral molecules manifests an enantiospecific preference in electron spin orientation. We therefore reasoned that the induced spin polarization may affect enantiorecognition through exchange interactions. Here we show experimentally that the interaction of chiral molecules with a perpendicularly magnetized substrate is enantiospecific. Thus, one enantiomer adsorbs preferentially when the magnetic dipole is pointing up, whereas the other adsorbs faster for the opposite alignment of the magnetization. The interaction is not controlled by the magnetic field per se, but rather by the electron spin orientations, and opens prospects for a distinct approach to enantiomeric separations.
Journal Article