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We report on the investigation of continuous -wave (CW) and SEmiconductor Saturable Absorber Mirror (SESAM) mode -locked operation of a Yb:GdScO3 laser. Using a single -transverse -mode, fiber -coupled InGaAs laser diode at 976 nm as a pump source, the Yb:GdScO3 laser delivers 343 mW output power at 1062 nm in the CW regime, which corresponds to a slope efficiency of 52%. Continuous tuning is possible across a wavelength range of 84 nm (1027-1111 nm). Using a commercial SESAM to initiate mode -locking and stabilize soliton-type pulse shaping, the Yb:GdScO3 laser produces pulses as short as 42 fs at 1065.9 nm, with an average output power of 40 mW at 66.89 MHz. To the best of our knowledge, this is the first demonstration of passively mode -locking with Yb:GdScO3 crystal.

A large-scale sub-5 nm nanofabrication technique is developed based on double layer anodized aluminium oxide (AAO) porous membrane masking. This technique also provides a facile route to form multilayer nano-arrays (metal nanoarrays sandwiched by AAO membranes), which is very challenging for other techniques. Normally the AAO mask has to be sacrificed, yet in this work it is preserved as a part of the nanostructure. The preserved AAO layers as the support for the second/third layer of the metal arrays provide a high-refractive index background for the multilayer metal arrays. This background concentrates the local E-field more significantly and results in a much higher Surface-Enhanced Raman Spectroscopy (SERS) signal than single layer metal arrays. This technique may lead to the advent of an inexpensive, reproducible, highly sensitive SERS substrate. Moreover, the physical essence of the plasmonic enhancement is unveiled by finite element method based numerical simulations. Enhancements from the gaps and the multilayer nanostructure agree very well with the experiments. The calculated layer-by-layer electric field distribution determines the contribution from different layers and provides more insights into the 3D textured structure.

A large-scale sub-5 nm nanofabrication technique is developed based on double layer anodized aluminium oxide (AAO) porous membrane masking. This technique also provides a facile route to form multilayer nano-arrays (metal nanoarrays sandwiched by AAO membranes), which is very challenging for other techniques. Normally the AAO mask has to be sacrificed, yet in this work it is preserved as a part of the nanostructure. The preserved AAO layers as the support for the second/third layer of the metal arrays provide a high-refractive index background for the multilayer metal arrays. This background concentrates the local E-field more significantly and results in a much higher Surface-Enhanced Raman Spectroscopy (SERS) signal than single layer metal arrays. This technique may lead to the advent of an inexpensive, reproducible, highly sensitive SERS substrate. Moreover, the physical essence of the plasmonic enhancement is unveiled by finite element method based numerical simulations. Enhancements from the gaps and the multilayer nanostructure agree very well with the experiments. The calculated layer-by-layer electric field distribution determines the contribution from different layers and provides more insights into the 3D textured structure.

Vertically aligned ZnO nanowire arrays were grown on ZnO single crystals using a chemical vapor deposition method. Nucleation sites were defined by patterning Au nanodot catalysts fabricated through anodized aluminum oxide (AAO) templates. Morphology and structure characterizations showed that the as-grown nanowires had the single-crystal hexagonal wurtzite structure with a <0001 > growth direction. By changing the pore distance of AAO, the density of nanowires could be well controlled. A sharp peak in the UV region and a weak broad peak in the visible region were shown in the room temperature photoluminescence spectra, suggesting the high-quality ZnO nanowire arrays were obtained. (C) 2015 Elsevier B.V. All rights reserved.

Aluminium (Al) nanoparticles (NPs) over a 1.2-cm(2) -size area are fabricated using nanoporous anodic aluminium oxide as shadow masks. With this technique, plasmon response of Al NP arrays with different out-of-plane height is investigated. The dipolar-localized surface plasmon resonances (LSPRs) peak of Al NP arrays is blueshifted and then redshifted slightly with an increase in particle height because of interparticle interactions. Moreover, a novel method is demonstrated to reduce the size of Al particle via removing the oxide shell by wet chemical etching and taking advantage of the rapid oxidization of the metal core upon exposure to atmosphere. Three kinds of acid solutions (mixture of H3PO4 and H2CrO4, H3PO4, and H2SO4) are demonstrated as effective etchants. By adjusting the etching conditions, the blueshift of LSPRs can be controlled precisely. Dipolar LSPR is obtained at wavelength down to 234 nm (5.3 eV), among the shortest ones ever observed in patterned Al NP arrays.

Vertically aligned ZnO nanowire arrays were grown on ZnO single crystals using a chemical vapor deposition method. Nucleation sites were defined by patterning Au nanodot catalysts fabricated through anodized aluminum oxide (AAO) templates. Morphology and structure characterizations showed that the as-grown nanowires had the single-crystal hexagonal wurtzite structure with a <0001 > growth direction. By changing the pore distance of AAO, the density of nanowires could be well controlled. A sharp peak in the UV region and a weak broad peak in the visible region were shown in the room temperature photoluminescence spectra, suggesting the high-quality ZnO nanowire arrays were obtained. (C) 2015 Elsevier B.V. All rights reserved.

Aluminium (Al) nanoparticles (NPs) over a 1.2-cm(2) -size area are fabricated using nanoporous anodic aluminium oxide as shadow masks. With this technique, plasmon response of Al NP arrays with different out-of-plane height is investigated. The dipolar-localized surface plasmon resonances (LSPRs) peak of Al NP arrays is blueshifted and then redshifted slightly with an increase in particle height because of interparticle interactions. Moreover, a novel method is demonstrated to reduce the size of Al particle via removing the oxide shell by wet chemical etching and taking advantage of the rapid oxidization of the metal core upon exposure to atmosphere. Three kinds of acid solutions (mixture of H3PO4 and H2CrO4, H3PO4, and H2SO4) are demonstrated as effective etchants. By adjusting the etching conditions, the blueshift of LSPRs can be controlled precisely. Dipolar LSPR is obtained at wavelength down to 234 nm (5.3 eV), among the shortest ones ever observed in patterned Al NP arrays.

Vertically aligned ZnO nanowire arrays were grown on ZnO single crystals using a chemical vapor deposition method. Nucleation sites were defined by patterning Au nanodot catalysts fabricated through anodized aluminum oxide (AAO) templates. Morphology and structure characterizations showed that the as-grown nanowires had the single-crystal hexagonal wurtzite structure with a <0001 > growth direction. By changing the pore distance of AAO, the density of nanowires could be well controlled. A sharp peak in the UV region and a weak broad peak in the visible region were shown in the room temperature photoluminescence spectra, suggesting the high-quality ZnO nanowire arrays were obtained. (C) 2015 Elsevier B.V. All rights reserved.

Aluminium (Al) nanoparticles (NPs) over a 1.2-cm(2) -size area are fabricated using nanoporous anodic aluminium oxide as shadow masks. With this technique, plasmon response of Al NP arrays with different out-of-plane height is investigated. The dipolar-localized surface plasmon resonances (LSPRs) peak of Al NP arrays is blueshifted and then redshifted slightly with an increase in particle height because of interparticle interactions. Moreover, a novel method is demonstrated to reduce the size of Al particle via removing the oxide shell by wet chemical etching and taking advantage of the rapid oxidization of the metal core upon exposure to atmosphere. Three kinds of acid solutions (mixture of H3PO4 and H2CrO4, H3PO4, and H2SO4) are demonstrated as effective etchants. By adjusting the etching conditions, the blueshift of LSPRs can be controlled precisely. Dipolar LSPR is obtained at wavelength down to 234 nm (5.3 eV), among the shortest ones ever observed in patterned Al NP arrays.

Surface water molecules induced grain boundaries (GBs) barrier modification was investigated in ZnO and ZnMgO/ZnO films. Tunable electronic transport properties of the samples by water were characterized via a field effect transistor (FET) device structure. The FETs fabricated from polar C-plane ZnO and ZnMgO/ZnO films that have lots of GBs exhibited obvious double Schottky-like current-voltage property, whereas that fabricated from nonpolar M-plane samples with GBs and ZnO bulk single-crystal had no obvious conduction modulation effects. Physically, these hallmark properties are supposed to be caused by the electrostatical coupling effect of crystal polar field and molecular dipole on GBs barrier. (C) 2014 AIP Publishing LLC.

Surface water molecules induced grain boundaries (GBs) barrier modification was investigated in ZnO and ZnMgO/ZnO films. Tunable electronic transport properties of the samples by water were characterized via a field effect transistor (FET) device structure. The FETs fabricated from polar C-plane ZnO and ZnMgO/ZnO films that have lots of GBs exhibited obvious double Schottky-like current-voltage property, whereas that fabricated from nonpolar M-plane samples with GBs and ZnO bulk single-crystal had no obvious conduction modulation effects. Physically, these hallmark properties are supposed to be caused by the electrostatical coupling effect of crystal polar field and molecular dipole on GBs barrier. (C) 2014 AIP Publishing LLC.

Surface water molecules induced grain boundaries (GBs) barrier modification was investigated in ZnO and ZnMgO/ZnO films. Tunable electronic transport properties of the samples by water were characterized via a field effect transistor (FET) device structure. The FETs fabricated from polar C-plane ZnO and ZnMgO/ZnO films that have lots of GBs exhibited obvious double Schottky-like current-voltage property, whereas that fabricated from nonpolar M-plane samples with GBs and ZnO bulk single-crystal had no obvious conduction modulation effects. Physically, these hallmark properties are supposed to be caused by the electrostatical coupling effect of crystal polar field and molecular dipole on GBs barrier. (C) 2014 AIP Publishing LLC.