Symmetry selective third harmonic generation from plasmonic metacrystals

Nonlinear processes are often governed by selection rules imposed by the symmetries of the molecular configurations. The most well-known examples include the role of mirror symmetry breaking for the generation of even harmonics, and the selection rule related to the rotation symmetry in harmonic generation for fundamental beams with circular polarizations. While the role of mirror symmetry breaking in second harmonic generation has been extensively studied in plasmonic systems, the investigation on selection rules pertaining to circular polarization states of harmonic generation has been limited to crystals, i.e. symmetries at the atomic level. Here we demonstrate the rotational symmetry dependent third harmonic generation from nonlinear plasmonic metacrystals. We show that the selection rule can be imposed by the rotational symmetry of meta-crystals embedded into an isotropic organic nonlinear thin film. The results presented here may open new avenues for designing symmetry-dependent nonlinear optical responses with tailored plasmonic nanostructures.Comment: 13 pages, 3 figure

Hexa­kis­(dimethyl sulfoxide-κO)nickel(II) bis­(2,2-dicyano­ethene-1,1-dithiol­ato-κ2 S,S′)nickelate(II)

The reaction of NiCl2·6H2O with sodium 2,2-dicyano­ethene-1,1-dithiol­ate [Na2(i-mnt)] in dimethyl sulfoxide produces the title complex, [Ni(C2H6OS)6][Ni(C4N2S2)2]. There is half each of an [Ni(C2H6OS)6]2− complex anion and an [Ni{(CH3)2SO}6]2+ complex cation in the asymmetric unit. The i-mnt ligand coordinates in a bidentate manner to the Ni atom in the anion through the two chelating S atoms in an approximate square-planar geometry. The Ni atom in the complex cation has an octahedral coordination environment with six dimethyl sulfoxide mol­ecules as ligands

Effect of Warm Acupuncture on “Dinghui Acupoint” and “Heart Acupoint” in Traditional Mongolian Medicine on Behaviors and Hypothalamic Inammatory Cytokines in Rats with Chronic Fatigue Syndrome

Objective: To observe the effects of warm acupuncture on “Dinghui Acupoint” and “Heart Acupoint” in Traditional Mongolian Medicine on behavior and hypothalamic inflammatory cytokines IL-1β, IL-6 and IFN-r in Rats with Chronic Fatigue Syndrome. Methods: SD rats were randomly divided into normal group, model group, warm acupuncture group and moxibustion positive control group. The latter three groups of rats were used to establish a model of rats with chronic fatigue syndrome (CFS) using a combination of physical fatigue and mental fatigue. When establishing the model of warm acupuncture group, “Dinghui Acupoint” and “Heart Acupoint” intervention was carried out; when establishing the model of moxibustion positive control group, “Zusanli Acupoint” intervention was carried out on both sides. Behavioral observations (body weight, exhaustive swimming time, tail suspension experiment, water maze) were performed before and after modeling. The hypothalamic inflammatory cytokines IL-1β, IL-6 and IFN-r were detected by ELISA method after warm acupuncture and moxibustion intervention. Results: After 21 days of modeling, the body weight of the rats in each group was significantly lower than that in the normal group, and there was a significant difference (P0.05); Compared with the normal group, IL-1β, IL-6 and IFN-r increased significantly in the model group and there was a significant difference (P0.05); Compared with the moxibustion group, the levels of IL-1β, IL-6 and IFN-r were not significantly different (P>0.05). Conclusion: Warm acupuncture on “Dinghui Acupoint” and “Heart Acupoint” in Traditional Mongolian Medicine has the ability to improve the body’s defense and self-healing ability, improve chronic fatigue syndrome (CFS), and thus play a preventive role. The results of this research indicate that the warm acupuncture group and the moxibustion group have the same effect

Deprojection technique for galaxy cluster considering point spread function

We present a new method for the analysis of Abell 1835 observed by XMM-Newton. The method is a combination of the Direct Demodulation technique and deprojection. We eliminate the effects of the point spread function (PSF) with the Direct Demodulation technique. We then use a traditional depro-jection technique to study the properties of Abell 1835. Compared to that of deprojection method only, the central electron density derived from this method increases by 30%, while the temperature profile is similar.Comment: accepted for publication in Sciences in China -- G, the Black Hole special issu

Giant nonlinear optical activity of achiral origin in planar metasurfaces with quadratic and cubic nonlinearities

3D chirality is shown to be unnecessary for introducing strong circular dichroism for harmonic generations. Specifically, near-unity circular dichroism for both second-harmonic generation and third-harmonic generations is demonstrated on suitably designed ultrathin plasmonic metasurfaces with only 2D planar chirality. The study opens up new routes for designing chip-type biosensing platform, which may allow for highly sensitive detection of bio- and chemical molecules with weak chirality