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1. Effect of Fabry-Perot Cavities on Concentration Quenching

   https://doi.org/10.1364/CLEO_AT.2019.JTh2A.20  

   Koutsares, S.; Prayakarao, S.; Courtwright, D.; Bonner, C. E.; Noginov, M. A. (January 2019, CLEO: QELS_Fundamental Science 2019)

   We show that concentration quenching of emission of dye molecules – an energy transfer to quenching centers – is inhibited in subwavelength Fabry-Perot cavities (or metal-insulator-metal, MIM, waveguides). 

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2. Effect of Fabry-Perot Cavities on Concentration Quenching

   S. Koutsares, S. Prayakarao (January 2019, Cleo)

   We show that concentration quenching of emission of dye molecules – an energy transfer to quenching centers – is inhibited in subwavelength Fabry-Perot cavities (or metal-insulator-metal, MIM, waveguides). 

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3. Evidence of First Stars-enriched Gas in High-redshift Absorbers*

   https://doi.org/10.3847/1538-4357/acc39f  

   Saccardi, Andrea; Salvadori, Stefania; D’Odorico, Valentina; Cupani, Guido; Fumagalli, Michele; Berg, Trystyn A.; Becker, George D.; Ellison, Sara; Lopez, Sebastian (May 2023, The Astrophysical Journal)

   Abstract The first stars were born from chemically pristine gas. They were likely massive, and thus they rapidly exploded as supernovae, enriching the surrounding gas with the first heavy elements. In the Local Group, the chemical signatures of the first stellar population were identified among low-mass, long-lived, very metal-poor ([Fe/H] < −2) stars, characterized by high abundances of carbon over iron ([C/Fe] > +0.7): the so-called carbon-enhanced metal-poor stars. Conversely, a similar carbon excess caused by first-star pollution was not found in dense neutral gas traced by absorption systems at different cosmic time. Here we present the detection of 14 very metal-poor, optically thick absorbers at redshift z ∼ 3–4. Among these, 3 are carbon-enhanced and reveal an overabundance with respect to Fe of all the analyzed chemical elements (O, Mg, Al, and Si). Their relative abundances show a distribution with respect to [Fe/H] that is in very good agreement with those observed in nearby very metal-poor stars. All the tests we performed support the idea that these C-rich absorbers preserve the chemical yields of the first stars. Our new findings suggest that the first-star signatures can survive in optically thick but relatively diffuse absorbers, which are not sufficiently dense to sustain star formation and hence are not dominated by the chemical products of normal stars. 

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4. Hybrid graphene-plasmon gratings

   https://doi.org/10.1063/5.0152664  

   Guo, Tianjing; Argyropoulos, Christos (August 2023, Journal of Applied Physics)

   Graphene can support surface plasmons with higher confinement, lower propagation loss, and substantially more tunable response compared to usual metal-based plasmonic structures. Interestingly, plasmons in graphene can strongly couple with nanostructures and gratings placed in its vicinity to form new hybrid systems that can provide a platform to investigate more complicated plasmonic phenomena. In this Perspective, an analysis on the excitation of highly confined graphene plasmons and their strong coupling with metallic or dielectric gratings is performed. We emphasize the flexibility in the efficient control of light–matter interaction by these new hybrid systems, benefiting from the interplay between graphene plasmons and other external resonant modes. The hybrid graphene-plasmon grating systems offer unique tunable plasmonic resonances with enhanced field distributions. They exhibit a novel route to realize practical emerging applications, including nonreciprocal devices, plasmonic switches, perfect absorbers, nonlinear structures, photodetectors, and optical sensors. 

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5. Influence of a suboptimal environment and sintering temperature on the mechanical properties of fused filament fabricated copper

   https://doi.org/10.1007/s00170-024-14697-z  

   Downard, Scott; Clark, Ethan; O’Brien, Cheosung; Mohammadlou, Bita Soltan; Kontsos, Antonios; Celli, Dino; Smith, Lucas; Al_Amiri, Essa; Weems, Andrew; Wisner, Brian (December 2024, The International Journal of Advanced Manufacturing Technology)

   Abstract   Metal injection molding (MIM) processes are generally more cost-effective for the generation of metallic AM components. However, the thermal processing required to remove the polymer and sinter the metal powder is not well understood in terms of resulting mechanical response and damage evolution, especially in ambient atmospheres where contamination is present. This study aims to provide a range of achievable mechanical properties of copper produced using a MIM-based method called fused filament fabrication (FFF) that is post-processed in a nonideal environment. These results showed direct correlations between sintering temperature to multiple aspects of material behavior. In addition, Nondestructive Evaluation (NDE) methods are leveraged to understand the variation in damage evolution that results from the processing, and it is shown that the higher sintering temperatures provided more desirable tensile properties for strength-based applications. Moreover, these results demonstrate a potential to tailor mechanical properties of FFF manufactured copper for a specific application. 

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