Design and characterization of a thermally stabilized fiber Fabry-Perot etalon as a wavelength calibrator for high-precision spectroscopy.

Filtering light from a broadband source with a Fabry-Perot etalon generates comb-like peaks in the spectral domain that can serve as calibration reference for precise Doppler shift detection on astronomical spectrographs. Fiber Fabry-Perot etalons are small in size and easily aligned optically. In application, high thermal sensitivity of the fiber core material requires a highly stable temperature control system.

Photo-induced luminescence degradation in Ce, Yb co-doped yttrium aluminum garnet phosphors.

Photon-induced luminescence degradation of Ce, Yb co-doped yttrium aluminum garnet phosphors with different Yb concentrations under 457 nm irradiation is studied for the first time, to the best of our knowledge. The degradation behavior is more significant in nano-phosphors prepared via the solgel method, compared with bulkier samples prepared via solid-state reaction. Photoluminescence intensity of Ce ions experiences a drop after initial illumination, due to photoionization of Ce ions, whereas the down-converted luminescence of Yb ions remains relatively stable.

Enabling low amounts of YAG:Ce(3+) to convert blue into white light with plasmonic Au nanoparticles.

We report a new strategy to directly attach Au nanoparticles onto YAG:Ce(3+) phosphor via a chemical preparation method, which yields efficient and quality conversion of blue to yellow light in the presence of a low amount of phosphor. Photoluminescent intensity and quantum yield of YAG:Ce(3+) phosphor are significantly enhanced after Au nanoparticle modification, which can be attributed to the strongly enhanced local surface electromagnetic field of Au nanoparticles on the phosphor particle surface. The CIE color coordinates shifted from the blue light (0.

Valley-selective circular dichroism of monolayer molybdenum disulphide.

A two-dimensional honeycomb lattice harbours a pair of inequivalent valleys in the k-space electronic structure, in the vicinities of the vertices of a hexagonal Brillouin zone, K(±). It is particularly appealing to exploit this emergent degree of freedom of charge carriers, in what is termed 'valleytronics'. The physics of valleys mimics that of spin, and will make possible devices, analogous to spintronics, such as valley filter and valve, and optoelectronic Hall devices, all very promising for next-generation electronics.

Anisotropic in-plane spin splitting in an asymmetric (001) GaAs/AlGaAs quantum well.

The in-plane spin splitting of conduction-band electron has been investigated in an asymmetric (001) GaAs/AlxGa1-xAs quantum well by time-resolved Kerr rotation technique under a transverse magnetic field. The distinctive anisotropy of the spin splitting was observed while the temperature is below approximately 200 K. This anisotropy emerges from the combined effect of Dresselhaus spin-orbit coupling plus asymmetric potential gradients.

Room temperature spin diffusion in (110) GaAs/AlGaAs quantum wells.

Transient spin grating experiments are used to investigate the electron spin diffusion in intrinsic (110) GaAs/AlGaAs multiple quantum well at room temperature. The measured spin diffusion length of optically excited electrons is about 4 μm at low spin density. Increasing the carrier density yields both a decrease of the spin relaxation time and the spin diffusion coefficient Ds.

[Clinical effect of Sonicare electric toothbrush in treating gingivitis].

Objective: To observe the clinical effect of Sonicare toothbrush in treating gingivitis by means of using Sonicare toothbrush in both healthy group and gingivitis group.

Methods: 50 medical students aged 18 to 25 years old were selected. At first,The gingival Index(GI) was examined and they were divided into 2 different groups.