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1. Deep learning 2D and 3D optical sectioning microscopy using cross-modality Pix2Pix cGAN image translation

   https://doi.org/10.1364/BOE.439894  

   Zhuge, Huimin; Summa, Brian; Hamm, Jihun; Brown, J_Quincy (November 2021, Biomedical Optics Express)

   Structured illumination microscopy (SIM) reconstructs optically-sectioned images of a sample from multiple spatially-patterned wide-field images, but the traditional single non-patterned wide-field images are more inexpensively obtained since they do not require generation of specialized illumination patterns. In this work, we translated wide-field fluorescence microscopy images to optically-sectioned SIM images by a Pix2Pix conditional generative adversarial network (cGAN). Our model shows the capability of both 2D cross-modality image translation from wide-field images to optical sections, and further demonstrates potential to recover 3D optically-sectioned volumes from wide-field image stacks. The utility of the model was tested on a variety of samples including fluorescent beads and fresh human tissue samples. 

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2. Switching of electrochemical selectivity due to plasmonic field-induced dissociation

   https://doi.org/10.1073/pnas.2404433121  

   Alcorn, Francis M; Kumar_Giri, Sajal; Chattoraj, Maya; Nixon, Rachel; Schatz, George C; Jain, Prashant K (October 2024, Proceedings of the National Academy of Sciences)

   Electrochemical reactivity is known to be dictated by the structure and composition of the electrocatalyst–electrolyte interface. Here, we show that optically generated electric fields at this interface can influence electrochemical reactivity insofar as to completely switch reaction selectivity. We study an electrocatalyst composed of gold–copper alloy nanoparticles known to be active toward the reduction of CO₂to CO. However, under the action of highly localized electric fields generated by plasmonic excitation of the gold–copper alloy nanoparticles, water splitting becomes favored at the expense of CO₂reduction. Real-time time-dependent density functional tight binding calculations indicate that optically generated electric fields promote transient-hole-transfer-driven dissociation of the O─H bond of water preferentially over transient-electron-driven dissociation of the C─O bond of CO₂. These results highlight the potential of optically generated electric fields for modulating pathways, switching reactivity on/off, and even directing outcomes. 

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3. LIGO tells us LINERs are not optically thick RIAFs

   https://doi.org/10.1093/mnrasl/slz116  

   Ford, K. E. Saavik; McKernan, B. (October 2019, Monthly Notices of the Royal Astronomical Society: Letters)

   ABSTRACT Low ionization nuclear emission-line regions (LINERs) are a heterogeneous collection of up to one-third of galactic nuclei in the local Universe. It is unclear whether LINERs are simply the result of low accretion rates onto supermassive black holes (BHs) or whether they include a large number of optically thick radiatively inefficient but super-Eddington accretion flows (RIAFs). Optically thick RIAFs are typically discs of large-scale height or quasi-spherical gas flows. These should be dense enough to trap and merge a large number of the stellar mass BHs, which we expect to exist in galactic nuclei. Electromagnetic observations of photospheres of accretion flows do not allow us to break model degeneracies. However, gravitational wave observations probe the interior of accretion flows where the merger of stellar mass BHs can be greatly accelerated over the field rate. Here, we show that the upper limits on the rate of BH mergers observed with LIGO demonstrate that most LINERs cannot be optically thick RIAFs. 

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4. Optically pumped white light-emitting diodes based on metal halide perovskites and perovskite-related materials

   https://doi.org/10.1063/1.5140441  

   Worku, Michael; Xu, Liang-Jin; Chaaban, Maya; Ben-Akacha, Azza; Ma, Biwu (January 2020, APL Materials)

   Optically pumped white light-emitting diodes (WLEDs), consisting of blue/ultraviolet LED chips and down conversion phosphors, have a wide range of applications in our daily life, such as full color display and solid-state lighting. While remarkable progress in light quality, device efficiency, and lifetime has been achieved during the last two decades, many challenges remain in optically pumped WLEDs, and searching for low cost high performance down conversion phosphors is still of great interest. Recently, metal halide perovskites have emerged as a highly promising new generation of light emitters for their exceptional optical properties with high quantum efficiencies and color tunability, which have also inspired researchers to investigate their derivatives. In this perspective, we briefly review the progress during the last few years in the development of metal halide perovskites and perovskite-related materials as down conversion phosphors for optically pumped WLEDs. We also highlight some major issues and challenges that need to be addressed to enable perovskite-based light emitters to possibly replace currently used rare-earth doped inorganic phosphors and quantum dots. 

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5. Multifunctional fluorescent nanocomposite of PVDF-TrFE and europium barium titanate

   https://doi.org/10.1063/5.0150084  

   McGinn, Christine K; Farahmand, Nasim; O’Brien, Stephen; Kymissis, Ioannis (August 2023, Journal of Applied Physics)

   Polyvinylidene difluoride trifluoroethylene (PVDF-TrFE) has received widespread application in flexible electronics and biomedical devices but is limited in its sensing modalities to piezoelectricity and pyroelectricity. The addition of optically or magnetically active nanoparticles could provide additional sensing modalities in the same element, which could drive miniaturization of such sensors. Europium barium titanate (EBTO) is one such optically active nanoparticle that could add functionality to such a nanocomposite. In this work, multifunctional nanocomposites of PVDF-TrFE and EBTO are successfully synthesized and characterized for their material and electronic properties. The nanocomposite in this work is the first known multifunctional nanocomposite with PVDF-TrFE and a fluorescent nanoparticle. 

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