AbstractMetasurfaces, composed of specifically designed subwavelength units in a two-dimensional plane, offer a new paradigm to design ultracompact optical elements that show great potentials for miniaturizing optical systems. In the past few decades, metasurfaces have drawn broad interests in multidisciplinary communities owing to their capability of manipulating various parameters of the light wave with plentiful functionalities. Among them, pixelated polarization manipulation in the subwavelength scale is a distinguished ability of metasurfaces compared to traditional optical components. However, the inherent ohmic loss of plasmonic-type metasurfaces severely hinders their broad applications due to the low efficiency. Therefore, metasurfaces composed of high-refractive-index all-dielectric antennas have been proposed to achieve high-efficiency devices. Moreover, anisotropic dielectric nanostructures have been shown to support large refractive index contrast between orthogonal polarizations of light and thus provide an ideal platform for polarization manipulation. Herein, we present a review of recent progress on all-dielectric metasurfaces for polarization manipulation, including principles and emerging applications. We believe that high efficient all-dielectric metasurfaces with the unprecedented capability of the polarization control can be widely applied in areas of polarization detection and imaging, data encryption, display, optical communication and quantum optics to realize ultracompact and miniaturized optical systems.

Black garlic is a new garlic product produced through fermentation of fresh garlic and is very popular in Asia countries due to its health benefits. Its key aroma-active compounds were characterized by gas chromatography–olfactometry–mass spectrometry (GC-O-MS), gas chromatography–time-of-flight mass spectrometry (GC-TOFMS), and sensory evaluation. In total 52 aroma compounds were identified, and 15 of them with high flavor dilution (FD) factors based on aroma extract dilution analysis (AEDA) were selected and quantitated. Finally, 9 key aroma-active compounds, including acetic acid (sour), allyl methyl trisulfide (cooked garlic), Furaneol (caramel), diallyldisulfide (garlic), diallyltrisulfide (sulfur), (E,Z)-2,6-nonadien-1-ol (cucumber), 3-methylbutanoic acid (sweat), 5-heptyldihydro-2­(3H)-furanone (apricot), and diallyl sulfide (garlic), were determined through aroma recombination and omission experiment. In addition to the sulfur-containing compounds, heterocyclic compounds were the major aroma contributors in black garlic. Sensory evaluation revealed that the flavor profile of black garlic mainly consisted of sulfur, sour, sweet, fresh, sauce, gasoline, and roasted odors.

Roasting, an important process to refine Wuyi Rock tea, could impart different types of aroma to the final products. This study focuses on the differences in aroma characteristics among three...

Controlling the morphology of nanowires in bottom-up synthesis and assembling them on planar substrates is of tremendous importance for device applications in electronics, photonics, sensing and energy conversion. To date, however, there remain challenges in reliably achieving these goals of orientation-controlled nanowire synthesis and assembly. Here we report that growth of planar, vertical and randomly oriented tin-doped indium oxide (ITO) nanowires can be realized on yttria-stabilized zirconia (YSZ) substrates via the epitaxy-assisted vapor-liquid-solid (VLS) mechanism, by simply regulating the growth conditions, in particular the growth temperature. This robust control on nanowire orientation is facilitated by the small lattice mismatch of 1.6% between ITO and YSZ. Further control of the orientation, symmetry and shape of the nanowires can be achieved by using YSZ substrates with (110) and (111), in addition to (100) surfaces. Based on these insights, we succeed in growing regular arrays of planar ITO nanowires from patterned catalyst nanoparticles. Overall, our discovery of unprecedented orientation control in ITO nanowires advances the general VLS synthesis, providing a robust epitaxy-based approach toward rational synthesis of nanowires.