Development of a flexible test-bed for robotics, telemanipulation and servicing research

The development of a flexible operation test-bed, based around a commercially available ASEA industrial robot is described. The test-bed was designed to investigate fundamental human factors issues concerned with the unique problems of robotic manipulation in the hostile environment of Space

Generation of tuneable 589nm radiation as a Na guide star source using an optical parametric amplifier

We describe a 5.5W 589nm source based on a passively modelocked Nd:YVO4 laser and a multi-stage Lithium Triborate optical parametric amplifier seeded by a tuneable semiconductor laser. We show this system can produce rapidly tuneable, transform-limited pulses in near diffraction-limited beams at 589nm, useful for Na guide star applications. The attraction of this scheme is that it can be assembled from commercially available hardware and is readily scalable to high average powers

Annealing-induced reduction in nanoscale heterogeneity of thermally evaporated amorphous As2S3 films

The morphology and structural order of thermally deposited and annealed amorphous As2S3 films have been investigated using high resolution transmission electron microscopy. It was found that both the as-deposited and annealed films contained sparsely distributed nanocrystallites of the orpiment As2S3 crystalline phase. However, from selected area electron diffraction both films appeared amorphous. Fluctuation electron microscopy revealed that the as-deposited film contained greater nanoscale inhomogeneity. Low temperature annealing reduced the nanoscale inhomogeneity and resulted in a more homogeneous and energetically favorable network. The reduction in nanoscale inhomogeneity upon low temperature annealing was accompanied by the appearance of a first sharp diffraction peak in the diffraction pattern. This first-sharp diffraction peak has been attributed to chemical ordering of interstitial voids. Our measurements suggest that this chemical short-range ordering is associated with the dissolution of the energetically unfavorable larger correlated structures that contribute to the inhomogeneity of the as-deposited film

Low loss high index contrast nanoimprinted polysiloxane waveguides

Nanoimprint lithography is gaining rapid acceptance in fields as diverse as microelectronics and microfluidics due to its simplicity high resolution and low cost. These properties are critically important for the fabrication of photonic devices, where cost is often the major inhibiting deployment factor for high volume applications. We report here on the use of nanoimprint technology to fabricate low loss broadband high index contrast waveguides in a Polysiloxane polymer system for the first time

Cluster formation through the action of a single picosecond laser pulse

We demonstrate experimentally and describe theoretically the formation of carbon nanoclusters created by single picosecond laser pulses. We show that the average size of a nanocluster is determined exclusively by single laser pulse parameters and is independent of the gas fill (He, Ar, Kr, Xe) and pressure in a range from 20mTorr to 200 Torr. Simple kinetic theory allows estimates to be made of the cluster size, which are in qualitative agreement with the experimental data. We conclude that the role of the buffer gas is to induce a transition between thin solid film formation on the substrate and foam formation by diffusing the clusters through the gas, with no significant effect upon the average cluster size

Picosecond high-repetition-rate pulsed laser ablation of dielectrics: the effect of energy accumulation between pulses

We report experiments on the ablation of arsenic trisulphide and silicon using high-repetition-rate (megahertz) trains of picosecond pulses. In the case of arsenic trisulphide, the average single pulse fluence at ablation threshold is found to be >100 times lower when pulses are delivered as a 76-MHz train compared with the case of a solitary pulse. For silicon, however, the threshold for a 4.1-MHz train equals the value for a solitary pulse. A model of irradiation by high-repetition-rate pulse trains demonstrates that for arsenic trisulphide energy accumulates in the target surface from several hundred successive pulses, lowering the ablation threshold and causing a change from the laser-solid to laser-plasma mode as the surface temperature increases

Laser-induced microexplosion confined in a bulk of silica: formation of nanovoids

We report on the nanovoid formation inside synthetic silica, viosil, by single femtosecond pulses of 30–100nJ energy, 800nm wavelength, and 180fs duration. It is demonstrated that the void is formed as a result of shock and rarefaction waves at pulse power much lower than the threshold of self-focusing. The shock-compressed region around the nanovoid is demonstrated to have higher chemical reactivity. This was used to reveal the extent of the shock-compressed region by wet etching. Application potential of nanostructuring of dielectrics is discussed

Thermal annealing of arsenic tri-sulphide thin film and its influence on device performance

Arsenic tri-sulphide (As₂S₃)thin filmwaveguides have been used successfully as nonlinear optical devices for all-optical signal processors. For such devices, low propagation loss is vital if high performance is to be obtained. In this study, thermal annealing was employed not only to stabilize the physical properties of the films, but also to reduce the sources of light attenuation in the as-deposited material. Here we investigated heat-induced changes to the microstructure and optical properties of As₂S₃thin films and, based on this information, determined the best annealing conditions. The refractive index of the films rises with annealing due to thermal densification and increased heteropolar bond density. The growth of surface roughness and thermal stress in the film, however, limits the annealing temperature to ∼130 °C. We fabricated and analyzed waveguides produced from as-deposited and annealedfilms and found that the propagation loss of the guides dropped by ∼0.2 dB/cm as a result of appropriate annealing.Rayleigh scattering and absorption from defects associated with phase separation, homopolar bonds, voids, and dangling bonds in the as-deposited film are shown to contribute to the higher light attenuation in unannealed films.This research was supported by the Australian Research Council through its Centre of Excellence program

Ambient Smell and the Retail Environment: Relating Olfaction Research to Consumer Behavior

This paper focuses on the use of ambient scent within retail environments, and investigates those mediating factors that help shape the emotional and behavioural responses that are stimulated. In doing so, it draws on the work of Mehrabian and Russell (1974), and attempts to contribute to the work on ambient scent in retailing by extending and elaborating the Gulas and Bloch (1995) model to encompass current research on human olfaction. The paper also introduces and specifically considers the ability of smell to communicate a ‘sense of place’, and its potential as a differentiator in a crowded marketplace