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1. High Verdet constant of Te ₂₀ As ₃₀ Se ₅₀ glass in the mid-infrared

   https://doi.org/10.1364/OL.390236  

   Mollaee, Masoud; Lucas, Pierre; Ari, Julien; Zhu, Xiushan; Lukowski, Michal; Manzur, Tariq; Peyghambarian, N. (January 2020, Optics Letters)
2. Secondary Proton Beam Instability in a Turbulent Solar Wind at 50 R _⊙

   https://doi.org/10.3847/1538-4357/acf656  

   Markovskii, S. A.; Vasquez, Bernard J. (September 2023, The Astrophysical Journal)

   Abstract We investigate a secondary proton beam instability coexisting with the ambient solar wind turbulence at 50R_☉. Three-dimensional hybrid numerical simulations (particle ions and a quasi-neutralizing electron fluid) are carried out with the plasma parameters in the observed range. In the turbulent background, the particle distribution function, in particular the slope of the “bump-on-tail” responsible for the instability, is time-dependent and inhomogeneous. The presence of the turbulence substantially reduces the growth rate and saturation level of the instability. We derive magnetic power spectra from the observational data and perform a statistical analysis to evaluate the average turbulence intensity at 50R_☉. This information is used to link the observed frequency spectrum to the wavenumber spectrum in the simulations. We verify that Taylor’s frozen-in hypothesis is valid for this purpose to a sufficient extent. To reproduce the typical magnetic power spectrum of the instability observed concurrently with the background turbulence, an artificial spacecraft probe is run through the simulation box. The thermal-ion instabilities are often seen as power elevations in the kinetic range of scales above an extrapolation of the turbulence spectrum from larger scales. We show that the elevated power in the simulations is much higher than the background level. Therefore, the turbulence at the average intensity does not obscure the secondary proton beam instability, as opposed to the solar wind at 1 au, in which the ambient turbulence typically obscures thermal-ion instabilities. 

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3. Fabrication of single color centers in sub-50 nm nanodiamonds using ion implantation

   https://doi.org/10.1515/nanoph-2022-0678  

   Xu, Xiaohui; Martin, Zachariah O.; Titze, Michael; Wang, Yongqiang; Sychev, Demid; Henshaw, Jacob; Lagutchev, Alexei S.; Htoon, Han; Bielejec, Edward S.; Bogdanov, Simeon I.; et al (January 2023, Nanophotonics)

   Abstract Diamond color centers have been widely studied in the field of quantum optics. The negatively charged silicon vacancy (SiV − ) center exhibits a narrow emission linewidth at the wavelength of 738 nm, a high Debye–Waller factor, and unique spin properties, making it a promising emitter for quantum information technologies, biological imaging, and sensing. In particular, nanodiamond (ND)-based SiV − centers can be heterogeneously integrated with plasmonic and photonic nanostructures and serve as in vivo biomarkers and intracellular thermometers. Out of all methods to produce NDs with SiV − centers, ion implantation offers the unique potential to create controllable numbers of color centers in preselected individual NDs. However, the formation of single color centers in NDs with this technique has not been realized. We report the creation of single SiV − centers featuring stable high-purity single-photon emission through Si implantation into NDs with an average size of ∼20 nm. We observe room temperature emission, with zero-phonon line wavelengths in the range of 730–800 nm and linewidths below 10 nm. Our results offer new opportunities for the controlled production of group-IV diamond color centers with applications in quantum photonics, sensing, and biomedicine. 

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4. 50 Grades of Shade

   https://doi.org/10.1175/BAMS-D-20-0193.1  

   MIDDEL, ARIANE; ALKHALED, SAUD; SCHNEIDER, FLORIAN A.; HAGEN, BJOERN; COSEO, PAUL (May 2021, Bulletin of the American Meteorological Society)

   null (Ed.)

   Abstract Cities increasingly recognize the importance of shade to reduce heat stress and adopt urban forestry plans with ambitious canopy goals. Yet, the implementation of tree and shade plans often faces maintenance, water use, and infrastructure challenges. Understanding the performance of natural and non-natural shade is critical to support active shade management in the built environment. We conducted hourly transects in Tempe, Arizona with the mobile human-biometeorological station MaRTy on hot summer days to quantify the efficacy of various shade types. We sampled sun-exposed reference locations and shade types grouped by urban form, lightweight/engineered shade, and tree species over multiple ground surfaces. We investigated shade performance during the day, at peak incoming solar, peak air temperature, and after sunset using three thermal metrics: the difference between a shaded and sun-exposed location in air temperature ( ΔT a ), surface temperature ( ΔT s ), and mean radiant temperature ( ΔT MRT ). ΔT a did not vary significantly between shade groups, but ΔT MRT spanned a 50°C range across observations. At daytime, shade from urban form most effectively reduced T s and T MRT , followed by trees and lightweight structures. Shade from urban form performed differently with changing orientation. Tree shade performance varied widely; native and palm trees were least effective, while non-native trees were most effective. All shade types exhibited heat retention (positive ΔT MRT ) after sunset. Based on the observations, we developed characteristic shade performance curves that will inform the City of Tempe’s design guidelines towards using “the right shade in the right place” and form the basis for the development of microclimate zones (MCSz). 

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5. Constraints on Sub-GeV Dark-Matter–Electron Scattering from the DarkSide-50 Experiment

   https://doi.org/10.1103/PhysRevLett.121.111303  

   Agnes, P.; Albuquerque, I. F.; Alexander, T.; Alton, A. K.; Araujo, G. R.; Asner, D. M.; Ave, M.; Back, H. O.; Baldin, B.; Batignani, G.; et al (September 2018, Physical Review Letters)