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1. Mid-Norwegian Margin Magmatism and Paleoclimate Implications

   https://doi.org/10.14379/iodp.proc.396.2023  

   Planke, S.; Berndt, C.; Alvarez Zarikian, C.A. (April 2023, Proceedings of the International Ocean Discovery Program Expedition reports)

   The opening of the northeast Atlantic, starting around 56 My ago, was associated with the emplacement of the North Atlantic Igneous Province, including the deposition of voluminous extrusive basaltic successions and intrusion of magma into the surrounding sedimentary basins. The mid-Norwegian Margin is a global type example of such a volcanic rifted margin and is well suited for scientific drilling with its thin sediment cover and good data coverage. During International Ocean Discovery Program Expedition 396, 21 boreholes were drilled at 10 sites in five different geological settings on the mid-Norwegian Margin. The boreholes sampled a wide variety of igneous and sedimentary settings ranging from lava flow fields to hydrothermal vent complexes, along with thick successions of Upper Paleocene and Lower Eocene strata. A comprehensive suite of wireline logs was collected in eight boreholes. These data provide new constraints for geodynamic models to explain the rapid emplacement of large igneous provinces and will also allow us to test the hypothesis that the Paleocene–Eocene Thermal Maximum (PETM) was caused by hydrothermal release of carbon in response to magmatic intrusions and/or flood basalt eruption. Successful drilling and high core recovery of target intervals at all nine primary sites and one additional alternate site will allow us to achieve these goals during postcruise work. Expedition 396 highlights include (1) drilling and coring a unique, multihole transect across a supra-sill hydrothermal system and crater that was filled in during the PETM, (2) drilling and coring all the major lithofacies at each of the component parts of a volcanic rifted margin from terrestrial to deep marine, and (3) acquiring excellent petrophysical data and imaging support for core analyses of complex and diverse volcanic and volcaniclastic intervals across the terrestrial to marine transition. 

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2. Atmospheric river changes shaped mid-latitude hydroclimate since the mid-Holocene

   https://doi.org/10.1016/j.epsl.2020.116293  

   Skinner, Christopher B.; Lora, Juan M.; Payne, Ashley E.; Poulsen, Christopher J. (July 2020, Earth and Planetary Science Letters)
3. Active mid-infrared ring resonators

   https://doi.org/10.1038/s41467-023-44628-7  

   Kazakov, Dmitry; Letsou, Theodore P; Beiser, Maximilian; Zhi, Yiyang; Opačak, Nikola; Piccardo, Marco; Schwarz, Benedikt; Capasso, Federico (December 2024, Nature Communications)

   Abstract High-quality optical ring resonators can confine light in a small volume and store it for millions of roundtrips. They have enabled the dramatic size reduction from laboratory scale to chip level of optical filters, modulators, frequency converters, and frequency comb generators in the visible and the near-infrared. The mid-infrared spectral region (3−12 μm), as important as it is for molecular gas sensing and spectroscopy, lags behind in development of integrated photonic components. Here we demonstrate the integration of mid-infrared ring resonators and directional couplers, incorporating a quantum cascade active region in the waveguide core. It enables electrical control of the resonant frequency, its quality factor, the coupling regime and the coupling coefficient. We show that one device, depending on its operating point, can act as a tunable filter, a nonlinear frequency converter, or a frequency comb generator. These concepts extend to the integration of multiple active resonators and waveguides in arbitrary configurations, thus allowing the implementation of purpose-specific mid-infrared active photonic integrated circuits for spectroscopy, communication, and microwave generation. 

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4. Observing the mid-latitude aurora

   https://doi.org/10.1117/12.2531275  

   Shaw, Joseph A.; Shaw, Joseph A.; Creath, Katherine; Lakshminarayanan, Vasudevan (August 2019, Proc. SPIE 11099)

   The aurora is a beautiful night sky optical phenomenon that is readily seen at high-latitude locations, but with more effort can also be seen and enjoyed at mid-latitude locations. Guidelines for when and where to look are presented, along with a rich array of photographic examples of mid-latitude auroras exhibiting all the usual range of green, red, and purple colors. 

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5. Nonlinear mid-infrared meta-membranes

   https://doi.org/10.1515/nanoph-2024-0203  

   Sartorello, Giovanni; Bocanegra, Joshua; Knez, David; Lukin, Daniil M; Yang, Joshua; Vučković, Jelena; Fishman, Dmitry A; Shvets, Gennady; Shcherbakov, Maxim R (August 2024, Nanophotonics)

   Nanophotonic structures have shown promising routes to controlling and enhancing nonlinear optical processes at the nanoscale. However, most nonlinear nanostructures require a handling substrate, reducing their application scope. Due to the underwhelming heat dissipation, it has been a challenge to evaluate the nonlinear optical properties of free-standing nanostructures. Here, we overcome this challenge by performing shot-controlled fifth harmonic generation (FHG) measurements on a SiC meta-membrane – a free-standing transmission metasurface with pronounced optical resonances in the mid-infrared (λres≈ 4,000 nm). Back focal plane imaging of the FHG diffraction orders and rigorous finite-difference time-domain simulations reveal at least two orders of magnitude enhancement of the FHG from the meta-membrane, compared to the unstructured SiC film of the same thickness. Single-shot measurements of the meta-membrane with varying resonance positions reveal an unusual spectral behavior that we explain with Kerr-driven intensity-dependent resonance dynamics. This work paves the way for novel substrate-less nanophotonic architectures. 

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