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In this work, we design and fabricate tunable pixelated infrared emitter arrays based on graphene transistors. We use finite element analysis to simulate a 5-by-3 pixelated emitter array, where localized heating area can be confined within a size of 25 μm and reaches more than 10 K temperature rise within 3 μs. By applying fast sweeping scheme with electrostatic voltage inputs, tunable surface patterns assembling dynamic alphabetical letters of microscale sizes are demonstrated and captured via thermal mapping with its thermal emission variation caused by localized temperature rise. Our results show that thermal emission can be highly localized and reconfigurable both spatially and temporally, which paves the way for developing and boosting the performance of microscale and nanoscale thermally driven devices for communication, characterization, sensing and actuation. 

Abstract Facing geographical barriers, phenotypic responses of migratory landbirds may differ even between closely related taxa: some may bypass barriers while others cross them. Such phenotypic variation can arise from different genetic backgrounds and lead to different adaptive processes. A classic example is migratory divide, i.e., breeding ranges where different migration-route phenotypes co-exist or meet. Such variation can facilitate an understanding of the evolutionary background of migration and responses to barriers. In Asia, a migratory divide has been suggested in response to the major landscape, the Qinghai-Tibet Plateau (QTP) for 2 stonechat taxa (Siberian stonechat Saxicola maurus maurus and Amur stonechat S. stejnegeri). Detouring along either side of the QTP, these taxa are believed to disfavor crossing over the highland. However, the Tibetan stonechat (S. m. przewalskii), breeding on the QTP, may differ in its barrier response due to possible adaptation to high elevation. To investigate migration patterns and potentially associated genetic differences, we studied migration routes and population genetics of populations around the assumed migratory divide in Russia and Mongolia and of a Chinese population from the QTP. Our results confirmed the existence of a migratory divide between maurus and stejnegeri, albeit with extensive hybridization over generations. Of the 3 genotyped individuals employing intermediate routes across the QTP, 2 were clear hybrids. Meanwhile, przewalskii consistently followed a highland-crossing route and was genetically differentiated from maurus and stejnegeri. The diverse migration routes indicate that Asian stonechats respond differently to the geographical barrier. The partly viable intermediate route may be associated with hybridization and potentially facilitating gene flow between maurus and stejnegeri. The Asian stonechat complex thus offers great opportunities for research, with its specific evolutionary background associated with inhabiting and crossing the QTP, offering novel perspectives on the genetics and evolution of migration. 

Plasmonic metasurfaces with adjustable optical responses can be achieved through phase change materials (PCMs) with high optical contrast. However, the on–off behavior of the phase change process results in the binary response of photonic devices, limiting the applications to the two-stage modulation. In this work, we propose a reconfigurable metasurface emitter based on a gold nanorod array on a VO2 thin film for achieving continuously tunable narrowband thermal emission. The electrode line connecting the center of each nanorod not only enables emission excitation electrically but also activates the phase transition of VO2 beneath the array layer due to Joule heating. The change in the dielectric environment due to the VO2 phase transition results in the modulation of emissivity from the plasmonic metasurfaces. The device performances regarding critical geometrical parameters are analyzed based on a fully coupled electro-thermo-optical finite element model. This new metasurface structure extends the binary nature of PCM based modulations to continuous reconfigurability and provides new possibilities toward smart metasurface emitters, reflectors, and other nanophotonic devices. 

Alkali metal anodes hold great promise for high-energy-density batteries for grid-scale applications.