25 research outputs found

    The impact of socioeconomic status and geographic location on Indigenous mortality in Australia, 1997-99

    Get PDF
    © Commonwealth of AustraliaAustralia's Aboriginal peoples and Torres Strait Islanders have the poorest health of any group in Australia. This has been the case for many years. Given that Australia has not made the advances in Indigenous health achieved in comparable countries (such as Canada, the United States and New Zealand), it is likely to be the case for some time. This report presents data describing one outcome of that poor health, namely premature deaths of Indigenous people. It examines the higher death rates experienced by Indigenous people in the context of socioeconomic disadvantage and geographic location (in particular, remoteness). The measures of disadvantage and location are, themselves, a reflection of the continuing historical and cultural environment in which Australia?s Indigenous peoples have lived since colonisation. As such they cannot fully explain why Indigenous death rates are as high as they are; nor can they explain why death rates for Indigenous people are so much higher than for the most disadvantaged non-Indigenous populations. To do that requires an understanding of the historical and cultural environment, a discussion which is beyond the scope of this report, but which has been addressed by others (HREOC 1997; PHAA Inc. 1997; Bartlett 1999). Data analysis can, however, inform our understanding of the extent and nature of differences in variations in Indigenous and non-Indigenous mortality

    Lasing mode pattern of a quantum cascade photonic crystal surface-emitting microcavity laser

    Get PDF
    The identification of the lasing mode within a quantum cascade photonic crystal microcavity laser emitting at λ ~8 µm is presented. The symmetry of the lasing mode is determined by the position of nodal lines within micro-bolometer camera measurements of its polarized spatial distribution. Full three-dimensional finite-difference time-domain simulations are also performed, and the resulting vertically emitted radiation field pattern is seen to follow the experimental results closely

    Quantum Cascade Surface-Emitting Photonic Crystal Laser

    Get PDF
    We combine photonic and electronic band structure engineering to create a surface-emitting quantum cascade microcavity laser. A high-index contrast two-dimensional photonic crystal is used to form a micro-resonator that simultaneously provides feedback for laser action and diffracts light vertically from the surface of the semiconductor surface. A top metallic contact allows electrical current injection and provides vertical optical confinement through a bound surface plasmon wave. The miniaturization and tailorable emission properties of this design are potentially important for sensing applications, while electrical pumping can allow new studies of photonic crystal and surface plasmon structures in nonlinear and near-field optics

    Quantum cascade photonic-crystal microlasers

    Get PDF
    We describe the realization of Quantum Cascade photonic-crystal microlasers. Photonic and electronic bandstructure engineering are combined to create a novel Quantum Cascade microcavity laser source. A high-index contrast two-dimensional photonic crystal forms a micro-resonator that provides feedback for laser action and diffracts light vertically from the surface of the semiconductor chip. A top metallic contact is used to form both a conductive path for current injection as well as to provide vertical optical confinement to the active region through a bound surface plasmon state at the metal-semiconductor interface. The device is miniaturized compared to standard Quantum Cascade technology, and the emission properties can in principle be engineered by design of the photonic crystal lattice. The combination of size reduction, vertical emission, and lithographic tailorability of the emission properties enabled by the use of a high-index contrast photonic crystal resonant cavity makes possible a number of active sensing applications in the mid- and far-infrared. In addition, the use of electrical pumping in these devices opens up another dimension of control for fundamental studies of photonic crystal and surface plasmon structures in linear, non-linear, and near-field optics

    Mid-IR quantum cascade lasers and amplifiers: recent developments and applications

    Get PDF
    This talk will give an overview of the most recent results on the realization of new quantum cascade laser devices and the perspective of their innovative applications in the mid-infrared range of the spectrum

    Quantum cascade photonic-crystal microlasers

    Get PDF
    We describe the realization of Quantum Cascade photonic-crystal microlasers. Photonic and electronic bandstructure engineering are combined to create a novel Quantum Cascade microcavity laser source. A high-index contrast two-dimensional photonic crystal forms a micro-resonator that provides feedback for laser action and diffracts light vertically from the surface of the semiconductor chip. A top metallic contact is used to form both a conductive path for current injection as well as to provide vertical optical confinement to the active region through a bound surface plasmon state at the metal-semiconductor interface. The device is miniaturized compared to standard Quantum Cascade technology, and the emission properties can in principle be engineered by design of the photonic crystal lattice. The combination of size reduction, vertical emission, and lithographic tailorability of the emission properties enabled by the use of a high-index contrast photonic crystal resonant cavity makes possible a number of active sensing applications in the mid- and far-infrared. In addition, the use of electrical pumping in these devices opens up another dimension of control for fundamental studies of photonic crystal and surface plasmon structures in linear, non-linear, and near-field optics

    On-orbit performance of the MIPS instrument

    Full text link
    The Multiband Imaging Photometer for Spitzer (MIPS) provides long wavelength capability for the mission, in imaging bands at 24, 70, and 160 microns and measurements of spectral energy distributions between 52 and 100 microns at a spectral resolution of about 7%. By using true detector arrays in each band, it provides both critical sampling of the Spitzer point spread function and relatively large imaging fields of view, allowing for substantial advances in sensitivity, angular resolution, and efficiency of areal coverage compared with previous space far-infrared capabilities. The Si:As BIB 24 micron array has excellent photometric properties, and measurements with rms relative errors of 1% or better can be obtained. The two longer wavelength arrays use Ge:Ga detectors with poor photometric stability. However, the use of 1.) a scan mirror to modulate the signals rapidly on these arrays, 2.) a system of on-board stimulators used for a relative calibration approximately every two minutes, and 3.) specialized reduction software result in good photometry with these arrays also, with rms relative errors of less than 10%
    corecore