Spin Unlocked Vortex Beam Generation on Nonlinear Chiroptical Metasurfaces.

Optical vortices with spin and orbital angular momentum (SAM and OAM) states offer multiple degrees of freedom for manipulating optical fields and thus enable great potentials in optical information processing. Recently, the optical metasurface has become an important platform for vortex beam generation and steering. However, the strong spin-orbit interaction on such metasurfaces usually leads to spin locked OAM generation, which limits the complete control of the angular momentum state of light.

All-optical ultrafast polarization switching with nonlinear plasmonic metasurfaces.

Optical switching has important applications in optical information processing, optical computing, and optical communications. The long-term pursuit of optical switch is to achieve short switching time and large modulation depth. Among various mechanisms, all-optical switching based on Kerr effect represents a promising solution.

Solar cycle as a distinct line of evidence constraining Earth's transient climate response.

Severity of warming predicted by climate models depends on their Transient Climate Response (TCR). Inter-model spread of TCR has persisted at ~ 100% of its mean for decades. Existing observational constraints of TCR are based on observed historical warming response to historical forcing and their uncertainty spread is just as wide, mainly due to forcing uncertainty, and especially that of aerosols.

A Centimeter-Scale Dielectric Metasurface for the Generation of Cold Atoms.

The single-beam magneto-optical trap (MOT) based on the diffractive optical element offers a new route to develop compact cold atom sources. However, the optical efficiency in the previous single-beam MOT systems is usually low and unbalanced, which will affect the quality of the trapped atoms. To solve this issue, we developed a centimeter-scale dielectric metasurface optical chip with dynamic phase distributions, which was used to split a single incident laser beam into five separate ones with well-defined polarization states and uniform energy distributions.

Seasonal Variations of Solar-Induced Fluorescence, Precipitation, and Carbon Dioxide Over the Amazon.

Previous studies suggested that the Amazon, the largest rainforest on Earth, changes from a CO sink to a CO source during the dry/fire season. However, the biospheric contributions to atmospheric CO are not well understood during the two main seasons, the dry/fire season and the wet season. In this article, we utilize Orbiting Carbon Observatory 2 (OCO-2) Solar-Induced Fluorescence (SIF) to explore photosynthetic activity during the different seasons.

Nonlinear vectorial holography with quad-atom metasurfaces.

Vectorial optical holography represents a solution to control the polarization and amplitude distribution of light in the Fourier space. While vectorial optical holography has been experimentally demonstrated in the linear optical regime, its nonlinear counterpart, which can provide extra degrees of freedom of light-field manipulation through the frequency conversion processes, remains unexplored. Here, we experimentally demonstrate the nonlinear vectorial holography through the second harmonic generation process on a quad-atom plasmonic metasurface.

High-Order Nonlinear Spin-Orbit Interaction on Plasmonic Metasurfaces.

In linear optics, the angular momentum of light can be easily manipulated through the optical spin-orbit interaction (SOI) in structured media such as liquid crystals, metasurfaces, and forked gratings. Similarly, metasurfaces can be used to generate nonlinear optical beams with both custom-defined spin angular momentum (SAM) and orbital angular momentum (OAM) states. However, it has been limited to a low-order process in which only a Gaussian-shaped fundamental wave is used.

Nonlinear Diatomic Metasurface for Real and Fourier Space Image Encoding.

In linear optics, the metasurface represents an ideal platform for encoding optical information because of its unprecedented abilities of manipulating the intensity, polarization, and phase of light wave with subwavelength meta-atoms. However, controlling various degrees of freedom of light in nonlinear optics remains elusive. Here, we propose a nonlinear plasmonic metasurface working in the near-infrared regime that can simultaneously encode optical images in the real and Fourier spaces.

A dielectric metasurface optical chip for the generation of cold atoms.

Compact and robust cold atom sources are increasingly important for quantum research, especially for transferring cutting-edge quantum science into practical applications. In this study, we report on a novel scheme that uses a metasurface optical chip to replace the conventional bulky optical elements used to produce a cold atomic ensemble with a single incident laser beam, which is split by the metasurface into multiple beams of the desired polarization states. Atom numbers ~10 and temperatures (about 35 μK) of relevance to quantum sensing are achieved in a compact and robust fashion.

Giant Enhancement of Second-Order Nonlinearity of Epsilon-near- Zero Medium by a Plasmonic Metasurface.

Nonlinear frequency conversion at the nanoscale is important for many applications in free space and integrated photonics. In epsilon-near-zero (ENZ) materials, second-harmonic generation (SHG) is significantly enhanced but the oblique incidence is required to address nonlinearity. To circumvent this constraint, we design a hybrid metasurface consisting of plasmonic nanostructures on an ENZ nanofilm generating strongly enhanced SHG at normal incidence in transmission.

Interdecadal variability in pan-Pacific and global SST, revisited.

Interest in the "Interdecadal Pacific Oscillation (IPO)" in the global SST has surged recently on suggestions that the Pacific may be the source of prominent interdecadal variations observed in the global-mean surface temperature possibly through the mechanism of low-frequency modulation of the interannual El Nino-Southern Oscillation (ENSO) phenomenon. IPO was defined by performing empirical orthogonal function (EOF) analysis of low-pass filtered SST. The low-pass filtering creates its unique set of mathematical problems-in particular, mode mixing-and has led to some questions, many unanswered.

Diatomic Metasurface for Vectorial Holography.

The emerging metasurfaces with the exceptional capability of manipulating an arbitrary wavefront have revived the holography with unprecedented prospects. However, most of the reported metaholograms suffer from limited polarization controls for a restrained bandwidth in addition to their complicated meta-atom designs with spatially variant dimensions. Here, we demonstrate a new concept of vectorial holography based on diatomic metasurfaces consisting of metamolecules formed by two orthogonal meta-atoms.

Midlatitude atmospheric OH response to the most recent 11-y solar cycle.

The hydroxyl radical (OH) plays an important role in middle atmospheric photochemistry, particularly in ozone (O(3)) chemistry. Because it is mainly produced through photolysis and has a short chemical lifetime, OH is expected to show rapid responses to solar forcing [e.g.

Design, synthesis, characterization, luminescence and non-linear optical (NLO) properties of multinuclear platinum(II) alkynyl complexes.

A series of luminescent multinuclear platinum(II) alkynyl complexes containing triethynylbenzene or 1,4-bis(3,5-diethynylphenyl)buta-1,3-diyne as cores has been successfully synthesized and characterized. The electronic absorption, emission, nanosecond transient absorption and electrochemical properties of these complexes have been reported. These complexes show long-lived emissions in degassed benzene solution and in alcoholic glass at 77 K.

Tropical mid-tropospheric CO2 variability driven by the Madden-Julian oscillation.

Carbon dioxide (CO(2)) is the most important anthropogenic greenhouse gas in the present-day climate. Most of the community focuses on its long-term (decadal to centennial) behaviors that are relevant to climate change, but there are relatively few discussions of its higher-frequency forms of variability, and none regarding its subseasonal distribution. In this work, we report a large-scale intraseasonal variation in the Atmospheric Infrared Sounder CO(2) data in the global tropical region associated with the Madden-Julian oscillation (MJO).

Atmospheric pressure as a natural climate regulator for a terrestrial planet with a biosphere.

Lovelock and Whitfield suggested in 1982 that, as the luminosity of the Sun increases over its life cycle, biologically enhanced silicate weathering is able to reduce the concentration of atmospheric carbon dioxide (CO(2)) so that the Earth's surface temperature is maintained within an inhabitable range. As this process continues, however, between 100 and 900 million years (Ma) from now the CO(2) concentration will reach levels too low for C(3) and C(4) photosynthesis, signaling the end of the solar-powered biosphere. Here, we show that atmospheric pressure is another factor that adjusts the global temperature by broadening infrared absorption lines of greenhouse gases.

Reactivity of aqua coordinated monoporphyrinate lanthanide complexes: synthetic, structural and photoluminescent studies of lanthanide porphyrinate dimers.

Dimerization of monoporphyrinate lanthanide complexes [Yb(Por)(H(2)O)(3)]Cl, (Por = TTP(2-), TMPP(2-) and TPP(2-)) in the presence of sterically hindered tripodal ligand, zinc Schiff-base, dilute HCl, K(2)CO(3) solution, 4,4'-bipyridine (bipy), and basic 8-hydroxyquinaldine (HQ) solution was observed in CH(2)Cl(2) at room temperature. Six neutral dimeric lanthanide porphyrinate complexes, [Yb(TTP)(mu-OH)](2)(mu-THF) (1), [Yb(TMPP)(mu-OH)(H(2)O)](2) (2), [Yb(TPP)(mu-OH)(mu-H(2)O)](2) (4), [Yb(TMPP)(mu-Cl)(H(2)O)](2) (5), [Yb(TMPP)(mu-OH)](2)(THF) (6) and [Yb(TPP)](2)(mu-OH)(mu-Q) (7), were obtained. X-Ray diffraction studies showed that for the dimers, the two lanthanide ions were bridged by OH(-), Cl(-) or H(2)O.

[Lanthanide ion luminescence probe: low temperature phase transition of EuS4N complex].

Fluorescence spectrum of EuS4N complex at low temperature is very different from that at room temperature. When temperature changes, shapes of both excitation and emission spectra change dramatically at about 160 K, which is taken as an indicator of the structural change of EuS4N. Peak splitting of 5D0-->7F0 also indicates that there are two different types of coordination structure for Eu3+ ions at low temperature, while only one at room temperature.

Syntheses, crystal structures, and physical properties of dinuclear copper(I) and tetranuclear mixed-valence copper(I,II) complexes with hydroxylated bipyridyl-like ligands.

Four copper complexes with hydroxylated bipyridyl-like ligands, namely [Cu(2)(ophen)(2)] (1), [Cu(4)(ophen)(4)(tp)] (2), [Cu(4)(obpy)(4)(tp)] (3), and [Cu(4)(obpy)(4)(dpdc)].2H(2)O (4), (Hophen=2-hydroxy-1,10-phenanthroline, Hobpy=6-hydroxy-2,2'-bipyridine, tp=terephthalate, dpdc=diphenyl-4,4'-dicarboxylate) have been synthesized hydrothermally. X-ray single-crystal structural analyses of these complexes reveal that 1,10-phenanthroline (phen) or 2,2'-bipyridine (bpy) ligands are hydroxylated into ophen or obpy during the reaction, which provides structural evidence for the long-time argued Gillard mechanism.