In this paper, we report anti-resonant silica hollow-core fibers (AR-HCFs) for solarization-free ultraviolet (UV) pulse transmission. The new fibers reported have lower attenuation than any previous HCFs for this spectral range. We report a single fiber that guides over a part of the UV-C and the whole of the UV-A spectral regions in adjacent transmission bands. A second AR-HCF is used for delivery of 17 nanosecond laser pulses at 266 nm at 30 kHz repetition rate. The fiber maintained a constant transmission, free of silica fluorescence and solarization-induced fiber degradation while delivering 0.46 μJ pulses for a period of over one hour. By direct comparison, we demonstrate that the single-mode AR-HCF significantly outperforms commercially-available high-OH and solarization-resistant silica multimode fibers for pulsed light delivery in this spectral range.

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Silver nanowires are one of the prominent candidates for the replacement of the incumbent indium tin oxide in thin and flexible electronics applications. Their main drawback is their inferior electrical robustness. Here, the mechanism of the short duration direct current induced failure in large networks is investigated by current stress tests and by examining the morphology of failures. It is found that the failures are due to the heating of the film and they initiate at the nanowire junctions, indicating that the main failure mechanism is based on the Joule heating of the junctions. This failure mechanism is different than what has been seen in literature for single nanowires and sparse networks. In addition, finite element heating simulations are performed to support the findings. Finally, we suggest ways of improving these films, in order to make them more suitable for device applications.

Raul et al. (2018) Percolating metallic structures templated on laser-deposited carbon nanofoams derived from graphene oxide: applications in humidity sensing. ACS Applied Nano Materials, 1 (4). pp. 1828-1835.

A Monte Carlo ray-trace model of nonideal microchannel plate (MCP) x-ray optics is described. The model takes into account angular misalignments, both transverse and axial, between the channels and the multifiber bundles; pincushion distortion of the square channels; radiusing of the channel vertices; and scattering from microroughness of the channel walls. The model also takes into account the spectrum and nonisotropic nature of the illuminating radiation. Using optical, scanning electron, and atomic force microscopies, as well as x-ray scattering data obtained with a laser plasma x-ray source, we have determined a partial error budget for the focusing action of a real square-pore MCP, leaving only the interchannel long-axis misalignment to be found by comparison of simulated and measured images. The power of the Monte Carlo model in directing the future development of MCP optics is illustrated.

Inkjet deposition can be a complementary technology to laser ablation to enable new processes. One such process is the One step interconnect for thin film photovoltaics, which is an improved method for series interconnection. The standard series interconnection process consists of three laser scribes between the deposition of the three key cell layers; transparent front contact, absorber layer and the metallic back contact. The one step interconnect allows the series interconnection to occur after the deposition of all layers significantly simplifying the manufacturing process. This is achieved by inkjet printing of conductive and insulative materials concurrently with depth selective laser scribes. The one step interconnect process has been shown to make effective interconnects on cadmium telluride photovoltaics with fill factors .60%. The benefits are many and include the reduction of capital equipment costs, reduced panel wastage and potentially improved material performance. The process is fully scalable and production ready.

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