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A monolithic polycapillary focusing optic was tested in the microbeam x-ray fluorescence system at the Oak Ridge Center for Manufacturing Technology. The optic was designed to cover a wide energy range from 4 keV to 20 keV. The focal spot size of the output beam at 17.4 keV (Mo Kα) was measured to be 21 μm full width of half maximum. An average beam intensity of 1.5×105 photon/s/μm2 was obtained at the focus for Mo Kα line using a 12 W microfocus x-ray source. This intensity is about 2400 times over that of a direct beam at 100 mm away from the x-ray source. The small, intense x-ray beam obtained was used to analyze and map the compositions of different elements in industrial samples.

Monolithic polycapillary focusing optics can collect a large solid angle of x rays from a point source and form intense focused beams for microbeam x‐ray fluorescence (MXRF) analysis. Such an optic was tested and characterized in a MXRF setup. For the Cu Kα line, the measured focal spot size of the optic was 43 μm full width at half‐maximum (FWHM). With the 16 W microfocusing x‐ray source (50 μm×10 μm), the average Cu Kα intensities over the focal spot was measured to be 8.9×104 photons/s/μm2. When compared to a straight single channel capillary optic with approximately the same output beam size, an intensity gain of 44 was obtained. The optic was applied to the MXRF setup to analyze trace elements in various samples and a minimum detection limit (MDL) of about 2 pg was achieved for the transition elements (V, Cr, Mn, and Fe). The optic was also used to map the distributions of trace elements in various samples.

We experimentally report the fabrication of deformed silica microtoroids with only one-axial symmetry and very large deformation reaching 18%. The largely deformed microcavities are demonstrated to support ultrahigh-Q resonant modes exceeding 6 × 107, though much more chaos emerges compared with slightly deformed microcavities. The chaotic behavior of rays is beneficial to enhance dynamical tunneling to high-Q whispering-gallery modes, and therefore allows efficient coupling by a free-space laser beam. The largely deformed microcavities hold great potential in applied photonics and fundamental studies.

We report Raman lasing in a slightly deformed silica microcavity using an efficient free-space coupling technique, with an absorbed pump threshold as low as 100 μW in the 1550 nm wavelength band. This ultralow threshold originates from the ultrahigh quality factors of whispering gallery modes, exceeding 108, even though the microcavity is deformed from a circular symmetry. Furthermore, the threshold of free-space coupled Raman lasing is experimentally demonstrated to show a strict inverse square dependence on the intrinsic quality factor of the cavity mode, which agrees well with the theoretical prediction.

CuI is used to control the molecular orientation of copper phthalocyanine (CuPc) and modify the anodes in organic solar cells based on CuPc/C60. By introducing a CuI buffer between indium tin oxide and CuPc, the power conversion efficiency is significantly enhanced by a factor of ∼70%. Because of the strong interactions between the CuI and CuPc, the stacking orientation of CuPc molecules is changed, resulting in a ∼65% increase in absorption coefficient, a larger carrier mobility and a smoother film surface. The anode work function is raised by the formation of a dipole layer.

By inserting a layer of (dibenzoylmethanato)3-(bathophenanthroline)-ytterbium (Yb–C) between copper phthalocyanine (CuPc) emitting layer and electron transport layer, intense and broadband electroluminescence (EL) were achieved at 930–1300nm spectral region in a phosphorescent EL device. The intensity and bandwidth are increased by about 50 and 4 times, respectively, compared with the EL device without Yb–C layer. The improvement in the EL intensity and band broadening were attributed to the energy transfer from Yb–C to CuPc and the overlapping of the Yb3+ near-infrared emission band with the CuPc emission band.