HIV-related Legal Needs, Demographic Change, and Trends in Australia since 1992: A Review of Legal Administrative Data.

An enabling legal environment is essential for an effective HIV response. Using legal administrative data from the HIV/AIDS Legal Centre (HALC), Australia's specialist HIV community legal service, this article characterizes the nature and trends in the legal issues and needs of those with HIV-related legal issues in New South Wales, Australia since 1992. At present, approximately 40% of all PLHIV living in NSW receive a legal service from HALC during the most recent five-year period. Clients received legal services relating to immigration law at a greatly increased rate (2010: 36%; 2019: 53%), discrimination matters decreased (2010: 17%; 2019: 5.9%), wills and estates remained steady (2010: 9%; 2019: 8.3%). Most clients identify as male (76.9%), homosexual (55%) and are aged between 35 and 49 years of age (34.6%). This demographic profile of clients changed over time, becoming younger and more likely to have been born overseas, and increasingly identifying as heterosexual.

The Legal Needs of People Living with a Sexually Transmissible Infection or Blood-Borne Virus: Perspectives From a Sample of the Australian Sexual Health and Blood Borne Virus Workforce.

Law and the legal environment are important factors in the epidemiology and prevention of sexually transmissible infections (STIs) and blood-borne viruses (BBVs). However, there has been no sustained effort to monitor the legal environment surrounding STIs and BBVs. This article presents the first data on the incidence and impacts of unmet legal needs for those affected by an STI or BBV in Australia using a survey administered to a sample of the Australian sexual health and BBV workforce. Migration, Housing, Money/Debt, Health (including complaints about health services), and Crime (accused/offender) were reported as the five most common legal need areas, with 60% of respondents describing these legal problems as generating a "severe" impact on health. These results indicate that unmet legal needs generate significant negative impacts in terms of individual health, on public health, and the ability to provide sustainable services such as testing and treatment to those facing unmet legal needs.

Regulating Health Care Safety: Enforcement and Responsibility Attribution in Response to Iatrogenic Harm.

The regulation of health care safety is undertaken in the name of the public and is motivated and justified by their protection. This regulatory action generates debate concerning the proper limits of responsibility attribution and enforcement, while the actions and opinion - both imagined and real - of the public loom large in this field. However, there exists limited knowledge of public opinion on key aspects of health care safety enforcement and responsibility attribution following iatrogenic harm. This article reports on the results of a survey-administered experimental study to determine how the Australian general public attributes responsibility, moral censure and enforcement actions in the event of health care safety failures in hospital and outpatient settings. The study provide evidence that the general public are sensitive to corporate and individual sources of error; attribute responsibility in a pluralistic manner; differentiate between recklessness and negligence; and will attempt both formal and social enforcement actions in response to harm.

Discrete dipole approximation in time domain through the Laplace transform.

We present a form of the discrete dipole approximation for electromagnetic scattering computations in time domain. We show that the introduction of complex frequencies, through the Laplace transform, significantly improves the computation time. We also show that the Laplace transform and its inverse can be combined to extract the field inside a scatterer at a real resonance frequency.

Electromagnetic forces on a discrete spherical invisibility cloak under time-harmonic illumination.

We study electromagnetic forces and torques on a discrete spherical invisibility cloak under time-harmonic illumination. We consider the influence of material absorption and losses, and we show that while the impact of absorption on the optical force remains confined to frequencies near the absorption peak, its impact on the electromagnetic torque experienced by the cloak is spectrally broader and follows the spectrum of the absorption cross section of the cloak. We also investigate the mechanical shielding of a test particle within the cloak. We find that even an imperfect cloak can reduce the radiation pressure on the particle significantly; however, under certain conditions the force on the particle can be stronger than it would be in the absence of the cloak.

Discrete dipole approximation for time-domain computation of optical forces on magnetodielectric scatterers.

We present a general approach, based on the discrete dipole approximation (DDA), for the computation of the exchange of momentum between light and a magnetodielectric, three-dimensional object with arbitrary geometry and linear permittivity and permeability tensors in time domain. The method can handle objects with an arbitrary shape, including objects with dispersive dielectric and/or magnetic material responses.

Discrete dipole approximation for the study of radiation dynamics in a magnetodielectric environment.

We develop a general computational approach, based on the discrete dipole approximation, for the study of radiation dynamics near or inside an object with arbitrary linear dielectric permittivity, and magnetic permeability tensors. Our method can account for dispersion and losses and provides insight on the role of local-field corrections in discrete magnetodielectric structures. We illustrate our method in the case of a source inside a magneto-dielectric, isotropic sphere for which the spontaneous emission rate of a source can be computed analytically. We show that our approach is in excellent agreement with the exact result, providing an approach capable of handling both the electric and magnetic response of advanced metamaterials.

Properties of sub-diffraction limited focusing by optical phase conjugation.

Recent work has demonstrated sub-diffraction limited focusing using time-reversal mirrors and sources in scattering media at microwave frequencies. We numerically investigate the possibility of observing analogous effects in the optical domain using small cylindrical scatterers of realistic dielectric materials combined with an enclosing optical phase conjugate mirror in two-dimensional geometries. Such focusing is possible but appears not to significantly exceed the focusing available from an equivalent homogenized material, and is highly sensitive to precise scatterer configuration.

Near-field and far-field analysis of an azimuthally polarized slow Bloch mode microlaser.

We report on the near- and far-field investigation of the slow Bloch modes associated with the Γ point of the Brillouin zone, for a honeycomb lattice photonic crystal, using near-field scanning optical microscopy (NSOM) and infra-red CCD camera. The array of doughnut-shaped monopolar mode (mode M) inside each unit cell, predicted previously by numerical simulation, is experimentally observed in the near-field by means of a metal-coated NSOM tip. In far-field, we detect the azimuthal polarization of the doughnut laser beam due to destructive and constructive interference of the mode radiating from the surface (mode TEM(01*)). A divergence of 2° for the laser beam and a mode size of (12.8 ± 1) µm for the slow Bloch mode at the surface of the crystal are also estimated.

Comparison of the sensitivity of air and dielectric modes in photonic crystal slab sensors.

Optical cavities provide a route to sensing through the shift of the optical resonant peak. However, effective sensing with optical cavities requires the optimization of the modal quality factor, Q, and the field overlap with the sample, f. For a photonic crystal slab (PCS) this figure of merit, M = fQ, involves two competing effects. The air modes usually have large f but small Q, whereas the dielectric modes have high-Q and small f. We compare the sensitivity of air and dielectric modes for different PCS cavity designs and account for loss associated with absorption by the sensed sample or its host liquid. We find that optimizing Q at the expense of f is the most beneficial strategy, and modes deriving from the dielectric bands are thus preferred.

Efficient iterative solution of the discrete dipole approximation for magnetodielectric scatterers.

The discrete dipole approximation (DDA) has been widely used to study light scattering by nonmagnetic objects. The electric field inside an arbitrary scatterer is found by solving a dense, symmetric, linear system using, in general, an iterative approach. However, when the scatterer has a nonzero magnetic susceptibility, the linear system becomes nonsymmetric, and some of the most commonly used iterative methods fail to work. We study the scattering of light by objects with both electric and magnetic linear responses and discuss the efficiency of several iterative solvers for the nonsymmetric DDA.

Room temperature low-threshold InAs/InP quantum dot single mode photonic crystal microlasers at 1.5 microm using cavity-confined slow light.

We have designed, fabricated, and characterized an InP photonic crystal slab structure that supports a cavity-confined slow-light mode, i.e. a bandgap-confined valence band-edge mode. Three dimensional finite difference in time domain calculations predict that this type of structure can support electromagnetic modes with large quality factors and small mode volumes. Moreover these modes are robust with respect to fabrication imperfections. In this paper, we demonstrate room-temperature laser operation at 1.5 mum of a cavity-confined slow-light mode under pulsed excitation. The gain medium is a single layer of InAs/InP quantum dots. An effective peak pump power threshold of 80 microW is reported.

Electromagnetic force and torque on magnetic and negative-index scatterers.

We derive the analytic expressions of the electromagnetic force and torque on a dipolar particle, with arbitrary dielectric permittivity and magnetic permeability. We then develop a general framework, based on the coupled dipole method, for computing the electromagnetic force and torque experienced by an object with arbitrary shape, dielectric permittivity and magnetic permeability.

Coupled-dipole method in time domain.

We present a time-domain formulation of electrodynamics based on the self-consistent derivation of the electromagnetic field in a linear, dispersive, lossy object via the coupled dipole method.

Microlasers based on effective index confined slow light modes in photonic crystal waveguides.

We present the design, theory and experimental implementation of a low modal volume microlaser based on a line-defect 2D-photonic crystal waveguide. The lateral confinement of low-group velocity modes is controlled by the post-processing of 1 to 3microm wide PMMA strips on top of two dimensional photonic crystal waveguides. Modal volume around 1.3 (lambda/n)(3) can be achieved using this scheme. We use this concept to fabricate microlaser devices from an InP-based heterostructure including InAs(0.65)P(0.35) quantum wells emitting around 1550nm and bonded onto a fused silica wafer. We observe stable, room-temperature laser operation with an effective lasing threshold around 0.5mW.

Local observation of modes from three-dimensional woodpile photonic crystals with near-field microspectroscopy under supercontinuum illumination.

A near-field microscope coupled with a near-infrared (NIR) supercontinuum source is developed and applied to characterize optical modes in a three-dimensional (3D) woodpile photonic crystal (PC) possessing a NIR partial bandgap. Spatially resolved near-field intensity distributions under different illumination wavelengths demonstrate that the electric fields preferentially dwell in the polymer rods or in the gaps between rods, respectively, for frequencies below or above the stop gap, as predicted by the 3D finite-difference time-domain modeling. Near-field microspectroscopy further reveals that the position-dependent band-edge effect plays an important role in PC-based all-optical integrated devices.

Confinement of band-edge modes in a photonic crystal slab.

We study the confinement of low group velocity band-edge modes in a photonic crystal slab. We use a rigorous, three dimensional, finite-difference time-domain method to compute the electromagnetic properties of the modes of the photonic structures. We show that by combining a defect mode approach with the high-density of states associated with bandedge modes, one can design compact, fabrication-tolerant, high-Q photonic microcavities. The electromagnetic confinement properties of these cavities can foster enhanced radiation dynamics and should be well suited for ultralow-threshold microlasers and cavity quantum electrodynamics.

Local-field enhancement in an optical force metallic nanotrap: application to single-molecule spectroscopy.

We study the local-field enhancement in a nanocavity created by optical nanomanipulation. Recently we showed that a metallic probe can modify the optical force experienced by a metallic particle and generate a material selective trapping potential. We show that the same configuration used for optical forces can be used to control both in magnitude and tune the local-field enhancement around the particle at resonance. The spatial resolution and material selectivity of this technique, allied to its capability to manipulate particles at the nanometric level, may offer a new and versatile way to achieve surface-enhanced Raman scattering spectroscopy at the single-molecule level.

Near-field observation of subwavelength confinement of photoluminescence by a photonic crystal microcavity.

We present a direct, room-temperature near-field optical study of light confinement by a subwavelength defect microcavity in a photonic crystal slab containing quantum-well sources. The observations are compared with three-dimensional finite-difference time-domain calculations, and excellent agreement is found. Moreover, we use a subwavelength cavity to study the influence of a near-field probe on the imaging of localized optical modes.