We have measured the spin-dependent nanometer-sized displacements of the spin Hall effect of the reflected light from a planar air-glass interface. In the case of the vertical polarization, the displacement is found to increase with the incident angle and subsequently decrease after approximately 48 deg, while in the case of the horizontal polarization, it changes rapidly near the Brewster angle. For a fixed incident angle of 30 deg, the displacement decreases to zero as the polarization angle approaches approximately 39 deg from 0 deg (the horizontal polarization) and then increases in the opposite direction until 90 deg (the vertical polarization).

We report on the observation of the spin separation of light in the plane of incidence when a linearly polarized beam is reflected or refracted at a planar dielectric interface. Remarkably, the in-plane spin separation reaches hundreds of nanometers, comparable with the transverse spin separation induced by the well-known spin Hall effect of light. The observation is properly explained by considering the in-plane spread of wave-vectors. This study thus offers new insights on the spinoptics and may provide a potential method to control light in optical nanodevices.

Abstract. Collocated sun photometer and nephelometer measurements at Tinga Tingana in the Australian Outback over the decade

Abstract. Classification of Australian continental aerosol types resulting from episodes of enhanced source activity, such as smoke plumes and dust outbreaks, is carried out via cluster analysis of optical properties obtained from inversion of sky radiance distributions at Australian aerosol ground stations using data obtained over the last decade. The cluster analysis distinguishes four significant classes, which are identified on the basis of their optical properties and provenance as determined by satellite imagery and backtrajectory analysis. The four classes are identified respectively as aged smoke, fresh smoke, coarse dust and a superabsorptive aerosol. While the first three classes show similarities with comparable aerosol types identified elsewhere, the super-absorptive aerosol has no obvious foreign prototype. The class identified as coarse dust shows a prominent depression in single scattering albedo in the blue spectral region due to absorption by hematite, which is shown to be more abundant in central Australian dust relative to the "dust belt"of the Northern Hemisphere. The super-absorptive class is distinctive in view of its very low single scattering albedo (∼0.7 at 500 nm) and variable enhanced absorption at 440 nm. The strong absorption by this aerosol requires a high black carbon content while the enhanced blue-band absorption may derive from organic compounds emitted during the burning of specific vegetation types. This aerosol exerts a positive radiative forcing at the top of atmosphere (TOA), with a large deposition of energy in the atmosphere per unit aerosol optical depth. This contrasts to the other three classes where the TOA forcing is negative. Optical properties of the four types will be used to improve the representation of Australian conCorrespondence to: R. M. Mitchell (ross.mitchell@csiro.au) tinental aerosol in climate models, and to enhance the accuracy of satellite-based aerosol retrievals over Australia.