A theory is presented for the development of circular polarization as radio waves propagate through the turbulent, birefringent interstellar medium. The fourth order moments of the wave field are calculated, and it is shown that unpolarized incident radiation develops a nonzero variance in circular polarization. A magnetized turbulent medium causes the Stokes parameters to scintillate in a nonidentical manner. A specific model for this effect is developed for the case of density fluctuations in a uniform magnetic field.
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http://dx.doi.org/10.1103/physreve.62.4177 | DOI Listing |
Using the first principle calculations, we propose a boron and nitrogen cluster incorporated graphene system for efficient valley polarization. The broken spatial inversion symmetry results in high Berry curvature at and valleys of the hexagonal Brillouin zone in this semiconducting system. The consideration of excitonic quasiparticles within the approximation along with their scattering processes using the many-body Bethe-Salpeter equation gives rise to an optical gap of 1.
View Article and Find Full Text PDFChem Asian J
January 2025
Universite de Rennes 1, Sciences Chimiques de Rennes - UMR 6226, Avenue du General Leclerc, Campus de Beaulieu, 35042, Rennes, FRANCE.
A novel coordination motif comprising [4]helicene fused with pyrazino-phenanthroline (H4PP) has been synthesized and reacted with ReCl(CO)5 to yield its rhenium(I) complex (Re-H4PP). Absorption and emission spectroscopic analysis conducted in dichloromethane and 2-methyltetrahydrofuran reveals that combining pyrazino-phenanthroline with helicene visibly affects the photophysical attributes of both the resulting ligand and its Re(I) complex as compared to their non-helicene analogues, and even more importantly leads to relatively high photoluminescence quantum yield values, especially in the case of H4PP (29%). Chiroptical studies through electronic circular dichroism and circularly polarized luminescence performed on enantiomerically enriched samples of Re-H4PP show the chiral nature of low-energy excited states affording notable glum values that amplify at cryogenic temperatures.
View Article and Find Full Text PDFACS Photonics
January 2025
Foundation of Research and Technology Hellas, Institute of Electronic Structure and Laser, Heraklion 71110, Greece.
We demonstrate a simple, low-cost, and ultracompact chiral resonant metasurface design, which, by strong local coupling to a quantum gain medium (quantum emitters), allows to implement an ultrathin metasurface laser, capable of generating tunable circularly polarized coherent lasing output. According to our detailed numerical investigations, the lasing emission can be transformed from linear to circular and switch from right- to left-handed circularly polarized (CP) not only by altering the metasurface chiral response but also by changing the polarization of a linearly polarized pump wave, thus enabling dynamic lasing-polarization control. Given the increasing interest for CP laser emission, our chiral metasurface laser design proves to be a versatile yet straightforward strategy to generate a strong and tailored CP emission laser, promising great potential for future applications in both photonics and materials science.
View Article and Find Full Text PDFACS Photonics
January 2025
Laboratory of Nanoscience for Energy Technologies (LNET), Faculty of Engineering (STI), Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne 1015, Switzerland.
Circular dichroism (CD) can distinguish the handedness of the chiral molecules. However, it is typically very weak due to vanishing absorption at low molecular concentrations. Here, we suggest thermal CD (TCD) for chiral detection, leveraging the temperature difference in the chiral sample when subjected to right- and left-circularly polarized excitations.
View Article and Find Full Text PDFACS Photonics
January 2025
Cardiff University School of Physics and Astronomy, The Parade, Cardiff CF24 3AA, United Kingdom.
The field of chiral nanoparticles is rapidly expanding, yet measuring the chirality of single nano-objects remains a challenging endeavor. Here, we report a technique to detect chiro-optical effects in single plasmonic nanoparticles by means of phase-sensitive polarization-resolved four-wave mixing interferometric microscopy. Beyond conventional circular dichroism, the method is sensitive to the particle polarizability, in amplitude and phase.
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