Nano-droplets deposited in microarrays by femtosecond Ti:sapphire laser-induced forward transfer

The authors present the deposition of nanoscale droplets of Cr using femtosecond Ti:Sapphire Laser-Induced Forward Transfer. Deposits around 300 nm in diameter, significantly smaller than any previously reported, are obtained from a 30 nm thick source film. Deposit size, morphology, and adhesion to a receiver substrate as functions of applied laser fluence are investigated. We show that deposits can be obtained from previously irradiated areas of the source material film with negligible loss of deposition quality, allowing sub-spot size period microarrays to be produced without the need to move the source film

Pulsed laser deposition for growth of high quality epitaxial garnet films for low threshold waveguide lasers

Pulsed laser deposition (PLD) is a mature technique capable of producing extremely high quality epitaxial single crystalline films. We have grown Nd:doped garnet films of GGG (Gd The talk will summarise our progress using conventional (single beam) PLD in thin-film and waveguide growth, using both nanosecond and femtosecond lasers, and also introduce our new directions in tri-beam PLD (three targets, three lasers) for growth of some interesting, complex and perhaps impossible structures, such as Gaussian doping, internal voids and even helically doped structures

Laser-direct-write methods for fabrication of paper-based medical diagnostic sensors

We demonstrate the use of laser-based direct-write methods, namely laser-induced forward transfer and laser-induced photo-polymerization as printing and patterning tools for the fabrication of paper-based fluidic sensors that enable affordable point-of-care medical diagnostics

Time-resolved imaging of flyer dynamics for femtosecond laser-induced backward transfer of solid polymer thin films

AbstractWe have studied the transfer regimes and dynamics of polymer flyers from laser-induced backward transfer (LIBT) via time-resolved shadowgraphy. Imaging of the flyer ejection phase of LIBT of 3.8μm and 6.4μm thick SU-8 polymer films on germanium and silicon carrier substrates was performed over a time delay range of 1.4–16.4μs after arrival of the laser pulse. The experiments were carried out with 150fs, 800nm pulses spatially shaped using a digital micromirror device, and laser fluences of up to 3.5J/cm2 while images were recorded via a CCD camera and a spark discharge lamp. Velocities of flyers found in the range of 6–20m/s, and the intact and fragmented ejection regimes, were a function of donor thickness, carrier and laser fluence. The crater profile of the donor after transfer and the resulting flyer profile indicated different flyer ejection modes for Si carriers and high fluences. The results contribute to better understanding of the LIBT process, and help to determine experimental parameters for successful LIBT of intact deposits

Apparatus to control and visualize the impact of a high-energy laser pulse on a liquid target

We present an experimental apparatus to control and visualize the response of a liquid target to a laser-induced vaporization. We use a millimeter-sized drop as target and present two liquid-dye solutions that allow a variation of the absorption coefficient of the laser light in the drop by seven orders of magnitude. The excitation source is a Q-switched Nd:YAG laser at its frequency-doubled wavelength emitting nanosecond pulses with energy densities above the local vaporization threshold. The absorption of the laser energy leads to a large-scale liquid motion at timescales that are separated by several orders of magnitude, which we spatiotemporally resolve by a combination of ultra-high-speed and stroboscopic high-resolution imaging in two orthogonal views. Surprisingly, the large-scale liquid motion at upon laser impact is completely controlled by the spatial energy distribution obtained by a precise beam-shaping technique. The apparatus demonstrates the potential for accurate and quantitative studies of laser-matter interactions.Comment: Submitted to Review of Scientific Instrument

Development of cyanide for feral pig and fox control

This report provides an overview of a series of pig- and fox-baiting research projects conducted 2005–2010. It is intended to collate and summarise the outcomes of these unpublished projects, including the completed pen and field trials, and provide recommendations for future research. This review will provide a useful reference document to support further research

Depth resolution of Piezoresponse force microscopy

Given that a ferroelectric domain is generally a three dimensional entity, the determination of its area as well as its depth is mandatory for full characterization. Piezoresponse force microscopy (PFM) is known for its ability to map the lateral dimensions of ferroelectric domains with high accuracy. However, no depth profile information has been readily available so far. Here, we have used ferroelectric domains of known depth profile to determine the dependence of the PFM response on the depth of the domain, and thus effectively the depth resolution of PFM detection

Space station common module network topology and hardware development

Conceptual space station common module power management and distribution (SSM/PMAD) network layouts and detailed network evaluations were developed. Individual pieces of hardware to be developed for the SSM/PMAD test bed were identified. A technology assessment was developed to identify pieces of equipment requiring development effort. Equipment lists were developed from the previously selected network schematics. Additionally, functional requirements for the network equipment as well as other requirements which affected the suitability of specific items for use on the Space Station Program were identified. Assembly requirements were derived based on the SSM/PMAD developed requirements and on the selected SSM/PMAD network concepts. Basic requirements and simplified design block diagrams are included. DC remote power controllers were successfully integrated into the DC Marshall Space Flight Center breadboard. Two DC remote power controller (RPC) boards experienced mechanical failure of UES 706 stud-mounted diodes during mechanical installation of the boards into the system. These broken diodes caused input to output shorting of the RPC's. The UES 706 diodes were replaced on these RPC's which eliminated the problem. The DC RPC's as existing in the present breadboard configuration do not provide ground fault protection because the RPC was designed to only switch the hot side current. If ground fault protection were to be implemented, it would be necessary to design the system so the RPC switched both the hot and the return sides of power

Near-infrared incoherent coupling and photorefractive response time of 'blue' Rh:BaTiO₃

We have investigated the time constants of writing and decay of photorefractive gratings in 'blue' Rh:BaTiO3 at visible and near-infrared wavelengths. High reflectivity (> 200 %) double phase conjugation has been achieved at near-infrared wavelengths (730 - 809 nm) and efficient double colour pumped oscillation has been demonstrated between wavelengths separated by 150 nm

3D geometric modelling of discontinuous fibre composites using a force-directed algorithm

A geometrical modelling scheme is presented to produce representative architectures for discontinuous fibre composites, enabling downstream modelling of mechanical properties. The model generates realistic random fibre architectures containing high filament count bundles (>3k) and high (~50%) fibre volume fractions. Fibre bundles are modelled as thin shells using a multi-dimension modelling strategy, in which fibre bundles are distributed and compacted to simulate pressure being applied from a matched mould tool. FE simulations are performed to benchmark the in-plane mechanical properties obtained from the numerical model against experimental data, with a detailed study presented to evaluate the tensile properties at various fibre volume fractions and specimen thicknesses. Tensile modulus predictions are in close agreement (less than 5% error) with experimental data at volume fractions below 45%. Ultimate tensile strength predictions are within 4.2% of the experimental data at volume fractions between 40%-55%. This is a significant improvement over existing 2D modelling approaches, as the current model offers increased levels of fidelity, capturing dominant failure mechanisms and the influence of out-of-plane fibres