Thickness dependency of nonlinear optical properties in ITO/Sn composite films

In this study,a batch of indium tin oxide(ITO)/Sn composites with different ratios was obtained based on the principle of thermal evaporation by an electron beam.The crystalline structure,surface shape,and optical characterization of the films were researched using an X-ray diffractometer,an atomic force microscope,a UV-Vis-NIR dual-beam spectrophotometer,and an open-hole Z-scan system.By varying the relative thickness ratio of the ITO/Sn bilayer film,tunable nonlinear optical properties were achieved.The nonlinear saturation absorption coefficientβmaximum of the ITO/Sn composites is−10.5×10^(−7)cm/W,approximately 21 and 1.72 times more enhanced compared to monolayer ITO and Sn,respectively.Moreover,the improvement of the sample nonlinear performance was verified using finite-difference in temporal domain simulations.

Deep-red emitting Mg2Ti04:Mn^(4+)phosphor ceramics for plant lighting

In this study,deep-red emitting Mg2T i04:Mn4 phosphor ceramics were synthesized by the high temperature solid-state reaction method.The ceramics can be excited by the 465 nm blue light and had a narrow emission with a full width at half maximum(FWMH)value of 31 nm.The peak wavelength was located at 658 nm,which matched the demanded wavelength for photosynthesis.The crystal field strength(Dq)and the Racah parameters(B and C)were estimated by the Tanabe-Sugano diagram.The thermal conductivity of the Mg2Ti(0.999)O4:0.001Mn^(4+)ceramic was 7.535 W/(m·K)at room temperature,which was one order of magnitude higher than that of the traditional packaging method using the silicone gel.A set of phosphor converted LEDs were fabricated by mounting the phosphor ceramics onto the 460 nm blue LED chips and the CIE coordinates can move from the blue region to the purple light region with the thickness of the ceramic increasing.These results indicated that the Mg2Ti04:Mn^(4+)phosphor ceramic was suitable for plant lighting when combined with a blue LED chip.

Electron-beam irradiation induced optical transmittance enhancement for Au/ITO and ITO/Au/ITO multilayer thin films

Electron beam（EB） irradiation experiments on Au/ITO and ITO/Au/ITO multilayer thin films are reported.The structure and the optical-electrical properties of the samples were investigated by X-ray diffraction,atomic force microscopy, four-point probe resistivity measurement system, and UV–vis-NIR double beam spectrometer, respectively. Those results show that the EB irradiation has the effects of improving the crystalline of samples, widening the optical band gap of both thin films, reducing the sheet resistance,and improving the transmittance of samples.

Influence of annealing temperature on the performance of TiO_(2)/SiO_(2) nanolaminated films

Different laminated structures of TiO_(2)/SiO_(2) composite film were prepared via atomic layer deposition(ALD)on alumina substrates.The effect of the annealing temperature in the air on the surface morphologies,crystal structures,binding energies,and ingredient content of these films was investigated using X-ray diffraction,field emission scanning electron microscopy,and X-ray photoelectron spectroscopy.Results showed that the binding energy of Ti and Si increased with decrease of the Ti content,and the TiO_(2)/SiO_(2) nanolaminated films exhibited a complex bonding structure.As the annealing temperature increased,the thickness of the nanolaminated films decreased,and the density and surface roughness increased.An increase in the crystallization temperature was proportional to the SiO_(2) content in TiO_(2)/SiO_(2) composite film.The annealing temperature and thin thickness strongly affected the phase structure of the ALD TiO_(2) thin film.To be specific,the TiO_(2) thin film transformed into an anatase phase from an amorphous phase after an increase in the annealing temperature from 400℃ to 550℃,and the TiO_(2) film exhibited an anatase phase until the annealing temperature reached 850℃,owing to its extremely small thickness.The annealing process caused the Al ions in the substrate to diffuse into the films and bond with 0.

Rapid fabrication of mini droplet lens array with tunable focal length

A rapid and cost-effective method for fabricating mini lens arrays is proposed. The lenses are made of silicone oil droplets and filled inside a polydimethylsiloxane(PDMS) elastomer. The lens arrays of different initial focal lengths and apertures can be fabricated by using the droplets of different volumes. Due to good elastic behavior of PDMS, the droplet lenses can be flexibly deformed, and the focal length and numerical aperture can be tuned by applying an external force on the PDMS elastomer. Furthermore, an apparatus for focal length tuning is designed and employed in the imaging system.