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Solid-state quantum light sources are being intensively investigated for applications in quantum technology. A key challenge is to extract light from host materials with high refractive index, where efficiency is limited by refraction and total internal reflection. Here we show that an index-matched solid immersion lens can, if placed sufficiently close to the semiconductor, extract light coupled through the evanescent field at the surface. Using both numerical simulations and experiments, we investigate how changing the thickness of the spacer between the semiconductor and lens impacts the collection efficiency (CE). Using automatic selection and measurement of 100 s of individually addressable colour centres in several aluminium nitride samples we demonstrate spacer-thickness dependent photon CE enhancement, with a mean enhancement factor of 4.2 and a highest measured photon detection rate of 743 kcps., Comment: 14 pages, 4 figures

Albedo, spectral slopes, and water ice band depths maps for the five midsized saturnian satellites Mimas, Enceladus, Tethys, Dione, and Rhea have been derived from Cassini-Visual and Infrared Mapping Spectrometer (VIMS) data. The maps are systematically built from photometric corrected data by applying the Kaasalainen-Shkuratov model (Kaasalainen et al., 2001, Shkuratov et al., 2011}. In this work a quadratic function is used to fit phase curves built by filtering observations taken with incidence angle $i\le70^\circ$, emission angle $e\le70^\circ$, phase angle $10^\circ \le g \le 120^\circ$, and Cassini-satellite distance $D \le 100.000$ km. This procedure is systematically repeated for a subset of 65 VIMS visible and near-infrared wavelengths for each satellite. The average photometric parameters are used to compare satellites' properties and to study their variability with illumination conditions changes. We derive equigonal albedo, extrapolated at g=0$^\circ$, not including the opposition effect, equal to 0.63$\pm$0.02 for Mimas, 0.89$\pm$0.03 for Enceladus, 0.74$\pm$0.03 for Tethys, 0.65$\pm$0.03 for Dione, 0.60$\pm$0.05 for Rhea at 0.55 $\mu$m. The knowledge of photometric spectral response allows to correct individual VIMS spectra used to build maps through geolocation. Maps are rendered at a fixed resolution corresponding to a $0.5^\circ \times 0.5^\circ$ bin on a longitude by latitude grid resulting in spatial resolutions of 1.7 km/bin for Mimas, 2.2 km/bin for Enceladus; 4.7 km/bin for Tethys; 4.5 km/bin for Dione; 6.7 km/bin for Rhea. These spectral maps allow establishing relationships with morphological features and with endogenic and exogenic processes capable to alter satellites' surface properties through several mechanisms..., Comment: 60 pages, 16 figures, 6 tables. Accepted for publication on Icarus journal

We describe the prediction, design, execution and calibration of stellar and solar occultation observations of Saturn's rings by the Visual and Infrared Mapping Spectrometer (VIMS) instrument on the Cassini spacecraft. Particular attention is paid to the technique developed for onboard acquisition of the stellar target and to the geometric and photometric calibration of the data. Examples of both stellar and solar occultation data are presented, highlighting several aspects of the data as well as the different occultation geometries encountered during Cassini's 13 year orbital tour. Complete catalogs of ring stellar and solar occultations observed by Cassini-VIMS are presented, as a guide to the standard data sets which have been delivered to the Planetary Data System's Ring Moon Systems Node., Comment: 90 Pages, 22 Figures, Accepted for Publication in Icarus

Over the last eight years, the Visual and Infrared Mapping Spectrometer (VIMS) aboard the Cassini orbiter has returned hyperspectral images in the 0.35-5.1 micron range of the icy satellites and rings of Saturn. These very different objects show significant variations in surface composition, roughness and regolith grain size as a result of their evolutionary histories, endogenic processes and interactions with exogenic particles. The distributions of surface water ice and chromophores, i.e. organic and non-icy materials, across the saturnian system, are traced using specific spectral indicators (spectral slopes and absorption band depths) obtained from rings mosaics and disk-integrated satellites observations by VIMS., Comment: Accepted for publication in the Astrophysical Journal (Part 1)

Saturn's main rings exhibit variations in both their opacity and spectral properties on a broad range of spatial scales, and the correlations between these parameters can provide insights into the processes that shape the composition and dynamics of the rings. The Visual and Infrared Mapping Spectrometer (VIMS) instrument onboard the Cassini Spacecraft has obtained spectra of the rings between 0.35 and 5.2 microns with sufficient spatial resolution to discern variations on scales below 200 km. These relatively high-resolution spectral data reveal that both the depths of the near-infrared water-ice absorption bands and the visible spectral slopes are often correlated with structural parameters such as the rings' optical depth. Using a simplified model for the ring-particles' regolith properties, we have begun to disentangle the trends due to changes in the gross composition of the ring particles from those that may be due to shifts in the texture of the ring particles' regolith. Consistent with previous studies, this analysis finds that the C ring and the Cassini Division possess enhanced concentrations of a contaminant that absorbs light over a broad range of wavelengths. On the other hand, a second contaminant that preferentially absorbs at short visible and near-ultraviolet wavelengths is found to be more evenly distributed throughout the rings. The optical activity of this short-wavelength absorber increases in the inner B ring inwards of 100,000 km from Saturn center, which may provide clues to the origin of this contaminant. The spectral variations identified as shifts in the regolith texture are in some places clearly correlated with the ring's optical depth, and in other locations they appear to be associated with the disturbances generated by strong mean-motion resonances with Saturn's various moons., Comment: 69 pages, 27 figures, accepted for publication in Icarus. Revised to reflect minor changes in text and figures made in proofs

In the last few years Cassini-VIMS, the Visible and Infared Mapping Spectrometer, returned to us a comprehensive view of the Saturn's icy satellites and rings. After having analyzed the satellites' spectral properties (Filacchione et al. (2007a)) and their distribution across the satellites' hemispheres (Filacchione et al. (2010)), we proceed in this paper to investigate the radial variability of icy satellites (principal and minor) and main rings average spectral properties. This analysis is done by using 2,264 disk-integrated observations of the satellites and a 12x700 pixels-wide rings radial mosaic acquired with a spatial resolution of about 125 km/pixel. The comparative analysis of these data allows us to retrieve the amount of both water ice and red contaminant materials distributed across Saturn's system and the typical surface regolith grain sizes. These measurements highlight very striking differences in the population here analyzed, which vary from the almost uncontaminated and water ice-rich surfaces of Enceladus and Calypso to the metal/organic-rich and red surfaces of Iapetus' leading hemisphere and Phoebe. Rings spectra appear more red than the icy satellites in the visible range but show more intense 1.5-2.0 micron band depths. The correlations among spectral slopes, band depths, visual albedo and phase permit us to cluster the saturnian population in different spectral classes which are detected not only among the principal satellites and rings but among co-orbital minor moons as well. Finally, we have applied Hapke's theory to retrieve the best spectral fits to Saturn's inner regular satellites using the same methodology applied previously for Rhea data discussed in Ciarniello et al. (2011)., Comment: 44 pages, 27 figures, 7 tables. Submitted to Icarus

Stellar occultations by Saturn's rings observed with the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft reveal that dusty features such as the F ring and the ringlets in the Encke and the Laplace Gaps have distinctive infrared transmission spectra. These spectra show a narrow optical depth minimum at wavelengths around 2.87 microns. This minimum is likely due to the Christiansen Effect, a reduction in the extinction of small particles when their (complex) refractive index is close to that of the surrounding medium. Simple Mie-scattering models demonstrate that the strength of this opacity dip is sensitive to the size distribution of particles between 1 and 100 microns across. Furthermore, the spatial resolution of the occultation data is sufficient to reveal variations in the transmission spectra within and among these rings. For example, in both the Encke Gap ringlets and F ring, the opacity dip weakens with increasing local optical depth, which is consistent with the larger particles being concentrated near the cores of these rings. The strength of the opacity dip varies most dramatically within the F ring; certain compact regions of enhanced optical depth lack an opacity dip and therefore appear to have a greatly reduced fraction of grains in the few-micron size range.Such spectrally-identifiable structures probably represent a subset of the compact optically-thick clumps observed by other Cassini instruments. These variations in the ring's particle size distribution can provide new insights into the processes of grain aggregation, disruption and transport within dusty rings. For example, the unusual spectral properties of the F-ring clumps could perhaps be ascribed to small grains adhering onto the surface of larger particles in regions of anomalously low velocity dispersion., Comment: 42 pages, 15 figures, accepted for publication in Icarus. A few small typographical errors fixed to match correction in proofs

The Cassini Division in Saturn's rings contains a series of eight named gaps, three of which contain dense ringlets. Observations of stellar occultations by the Visual and Infrared Mapping Spectrometer onboard the Cassini spacecraft have yielded ~40 accurate and precise measurements of the radial position of the edges of all of these gaps and ringlets. These data reveal suggestive patterns in the shapes of many of the gap edges: the outer edges of the 5 gaps without ringlets are circular to within 1 km, while the inner edges of 6 of the gaps are eccentric, with apsidal precession rates consistent with those expected for eccentric orbits near each edge. Intriguingly, the pattern speeds of these eccentric inner gap edges, together with that of the eccentric Huygens ringlet,form a series with a characteristic spacing of 0.06 degrees/day. The two gaps with non-eccentric inner edges lie near first-order Inner Lindblad Resonances (ILRs) with moons. One such edge is close to the 5:4 ILR with Prometheus. The other resonantly confined edge is the outer edge of the B ring, which lies near the 2:1 Mimas ILR. Detailed investigation of the B-ring-edge data confirm the presence of an m=2 perturbation on the B-ring edge, but also suggest that this pattern moves or librates relative to Mimas. The B-ring edge also has an m=1 component that rotates around the planet at a rate close to the expected apsidal precession rate. The pattern speeds of the eccentric edges in the Cassini Division can potentially be generated from various combinations of the pattern speeds of structures observed on the edge of the B ring. We therefore suggest that the locations of most of the gaps in the Cassini Division may be determined by resonances involving a combination of perturbations from Mimas and the massive edge of the B ring., Comment: 47 pages, 12 figures, accepted for publication in the Astronomical Journal, Some small typographical and wording errors fixed

Titan is one of the primary scientific objectives of the NASA ESA ASI Cassini Huygens mission. Scattering by haze particles in Titan's atmosphere and numerous methane absorptions dramatically veil Titan's surface in the visible range, though it can be studied more easily in some narrow infrared windows. The Visual and Infrared Mapping Spectrometer (VIMS) instrument onboard the Cassini spacecraft successfully imaged its surface in the atmospheric windows, taking hyperspectral images in the range 0.4 5.2 ?m. On 26 October (TA flyby) and 13 December 2004 (TB flyby), the Cassini Huygens mission flew over Titan at an altitude lower than 1200 km at closest approach. We report here on the analysis of VIMS images of the Huygens landing site acquired at TA and TB, with a spatial resolution ranging from 16 to14.4 km/pixel. The pure atmospheric backscattering component is corrected by using both an empirical method and a first-order theoretical model. Both approaches provide consistent results. After the removal of scattering, ratio images reveal subtle surface heterogeneities. A particularly contrasted structure appears in ratio images involving the 1.59 and 2.03 ?m images north of the Huygens landing site. Although pure water ice cannot be the only component exposed at Titan's surface, this area is consistent with a local enrichment in exposed water ice and seems to be consistent with DISR/Huygens images and spectra interpretations. The images show also a morphological structure that can be interpreted as a 150 km diameter impact crater with a central peak.

Images from instruments on Cassini as well as from telescopes on the ground reveal the presence of sporadic small-scale cloud activity in the cold late-winter north polar of Saturn's large moon Titan. These clouds lie underneath the previously discovered uniform polar cloud attributed to a quiescent ethane cloud at ~40 km and appear confined to the same latitudes as those of the largest known hydrocarbon lakes at the north pole of Titan. The physical properties of these clouds suggest that they are due to methane convection and condensation. Such convection has not been predicted for the cold winter pole, but can be caused by a process in many ways analogous to terrestrial lake-effect clouds. The lakes on Titan are a key connection between the surface and the meteorological cycle., Comment: 11 pages, 3 figures

The entry of the Cassini-Huygens spacecraft into orbit around Saturn in July 2004 marked the start of a golden era in the exploration of Titan, Saturn's giant moon. During the prime mission (2004-2008), ground-breaking discoveries were made by the Cassini orbiter including the equatorial dune fields (flyby T3, 2005), northern lakes and seas (T16, 2006), and the large positive and negative ions (T16 & T18, 2006), to name a few. In 2005 the Huygens probe descended through Titan's atmosphere, taking the first close-up pictures of the surface, including large networks of dendritic channels leading to a dried-up seabed, and also obtaining detailed profiles of temperature and gas composition during the atmospheric descent. The discoveries continued through the Equinox mission (2008-2010) and Solstice mission (2010-2017) totaling 127 targeted flybys of Titan in all. Now at the end of the mission, we are able to look back on the high-level scientific questions from the start of the mission, and assess the progress that has been made towards answering these. At the same time, new scientific questions regarding Titan have emerged from the new discoveries that have been made. In this paper we review a cross-section of important scientific questions that remain partially or completely unanswered, ranging from Titan's deep interior to the exosphere. Our intention is to help formulate the science goals for the next generation of planetary missions to Saturn and Titan, and to stimulate new experimental, observation and theoretical investigations in the interim, before such missions arrive again at Titan.

Recently developed CRISM parameters and newly available DTMs are enabling refined characterization of the mineralogy at Mawrth Vallis. A stratigraphy including 5 units is mapped using HRSC DTMs across 100s of kms and using HiRISE DTMs across 100s of meters. Transitions in mineralogic units were characterized using spectral properties and surface morphology. The observations point to an ancient wet and warm geologic record that formed the thick nontronite unit, a period of wet/dry cycling to create acid alteration, followed by leaching or pedogenesis to result in Al-phyllosilicates, and finally a drier, colder climate that left the altered ash in the form of nanophase aluminosilicates, rather than crystalline clays.

Space weathering produces well-known optical effects in silicate minerals in the inner Solar System, for example, on the Moon. Space weathering from solar wind and UV (ultraviolet radiation) is expected to be significantly weaker in the outer Solar System simply because intensities are low. However, cosmic rays and micrometeoroid bombardment would be similar to first order. That, combined with the much higher volatility of icy surfaces means there is the potential for space weathering on icy outer Solar System surfaces to show optical effects. The Cassini spacecraft orbiting Saturn is providing evidence for space weathering on icy bodies. The Cassini Visible and Infrared Mapping Spectrometer (VIMS) instrument has spatially mapped satellite surfaces and the rings from 0.35-5 microns and the Ultraviolet Imaging Spectrograph (UVIS) instrument from 0.1 to 0.2 microns. These data have sampled a complex mixing space between H2O ice and non-ice components and they show some common spectral properties. Similarly, spectra of the icy Galilean satellites and satellites in the Uranian system have some commonality in spectral properties with those in the Saturn system. The UV absorber is spectrally similar on many surfaces. VIMS has identified CO2, H2 and trace organics in varying abundances on Saturn's satellites. We postulate that through the spatial relationships of some of these compounds that they are created and destroyed through space weathering effects. For example, the trapped H2 and CO2 observed by VIMS in regions with high concentrations of dark material may in part be space weathering products from the destruction of H2O and organic molecules. The dark material, particularly on Iapetus which has the highest concentration in the Saturn system, is well matched by space-weathered silicates in the .4 to 2.6 micron range, and the spectral shapes closely match those of the most mature lunar soils, another indicator of space weathered material.

Cassini ISS observed multiple widespread changes in surface brightness in Titan's equatorial regions over the past three years. These brightness variations are attributed to rainfall from cloud systems that appear to form seasonally. Determining the composition of this rainfall is an important step in understanding the "methanological" cycle on Titan. I use data from Cassini VIMS to complete a spectroscopic investigation of multiple rain-wetted areas. I compute "before-and-after" spectral ratios of any areas that show either deposition or evaporation of rain. By comparing these spectral ratios to a model of liquid ethane, I find that the rain is most likely composed of liquid ethane. The spectrum of liquid ethane contains multiple absorption features that fall within the 2-micron and 5-micron spectral windows in Titan's atmosphere. I show that these features are visible in the spectra taken of Titan's surface and that they are characteristically different than those in the spectrum of liquid methane. Furthermore, just as ISS saw the surface brightness reverting to its original state after a period of time, I show that VIMS observations of later flybys show the surface composition in different stages of returning to its initial form.

The Moon Mineralogy Mapper (M3), a NASA Discovery Mission of Opportunity, was launched October 22, 2008 from Shriharikota in India on board the Indian ISRO Chandrayaan- 1 spacecraft for a nominal two-year mission in a 100-km polar lunar orbit. M3 is a high-fidelity imaging spectrometer with 260 spectral bands in Target Mode and 85 spectral bands in a reduced-resolution Global Mode. Target Mode pixel sizes are nominally 70 meters and Global pixels (binned 2 by 2) are 140 meters, from the planned 100-km orbit. The mission was cut short, just before halfway, in August, 2009 when the spacecraft ceased operations. Despite the abbreviated mission and numerous technical and scientific challenges during the flight, M3 was able to cover more than 95% of the Moon in Global Mode. These data, presented and analyzed here as a global whole, are revolutionizing our understanding of the Moon. Already, numerous discoveries relating to volatiles and unexpected mineralogy have been published [1], [2], [3]. The rich spectral and spatial information content of the M3 data indicates that many more discoveries and an improved understanding of the mineralogy, geology, photometry, thermal regime and volatile status of our nearest neighbor are forthcoming from these data. Sadly, only minimal high-resolution Target Mode images were acquired, as these were to be the focus of the second half of the mission. This abstract gives the reader a global overview of all the M3 data that were collected and an introduction to their rich spectral character and complexity. We employ a Principal Components statistical method to assess the underlying dimensionality of the Moon as a whole, as seen by M3, and to identify numerous areas that are low-probability targets and thus of potential interest to selenologists.

The Cassini Visual and Infrared Mapping Spectrometer (VIMS) is an imaging spectrometer on the Cassini spacecraft that covers the spectral range of 0.35 - 5.2 m in 352 spectral channels, a nominal instantaneous field of view of 0.5 mrad and an image format of 64 x 64 pixels. It has completed it s first 6 months in orbit around Saturn. During that time it has made extensive observations of Saturn s rings, it s icy satellites, in particular Phoeba and Iapetus, and had 1 distant and 2 close flybys of Titan.

Infrared spectra of ammonia-water ice mixtures reveal temperature-dependent absorption bands due to ammonia. These features, at 1.04, 2.0, and 2.25 microns, may shed light on the surface compositions of the Galilean and Saturnian satellites. Additional information is contained in the original extended abstract.

The Thermal Emission Spectrometer on board the Mars Global Surveyor has observed "White Rock" and the data do not indicate the presence of evaporite minerals. We suggest it is a deposit of compacted or weakly cemented aeolian sediment.

The Thermal Emission Spectrometer (TES) instrument on the Mars Global Surveyor (MGS) mission has discovered a remarkable accumulation of crystalline hematite ((alpha-Fe2O3) that covers an area with very sharp boundaries approximately 350 by 350-750 km in size centered near 2 S latitude between 0 and 5 W longitude (Sinus Meridiani). Crystalline hematite is uniquely identified by the presence of fundamental vibrational absorption features centered near 300, 450, and >525/cm, and by the absence of silicate fundamentals in the 1000/cm region. Spectral features resulting from atmospheric CO2, dust, and water ice were removed using a radiative transfer model. The spectral properties unique to Sinus Meridiani were emphasized by removing the average spectrum of the surrounding region. The depth and shape of the hematite fundamental bands show that the hematite is crystalline and relatively coarse grained (>5-10 micron). Diameters up to and greater than 100s of micrometers are permitted within the instrumental noise and natural variability of hematite spectra. Hematite particles <5-10 micron in diameter (either as an unpacked or hard-packed powders) fail to match the TES spectra. The spectrally-derived areal abundance of hematite varies with particle size from approximately 10% for particles >30 micron in diameter to 40-60% for unpacked 10 micron powders. The hematite in Sinus Meridiani is thus distinct from the fine-grained (diameter <5-10 micron), red, crystalline hematite considered, on the basis of visible, near-IR data, to be a minor spectral component in Martian bright regions like Olympus-Amazonis. Sinus Meridiani hematite is closely associated with a smooth, layered, friable surface that is interpreted to be sedimentary in origin. This material may be the uppermost surface in the region, indicating that it could be a late-stage sedimentary unit, or it could be a layered portion of the heavily cratered plains units. We consider five possible mechanisms for the formation of coarse-grained, crystalline hematite. These processes fall into two classes depending on whether they require a significant amount of near-surface water: (1) chemical precipitation that includes origin by (a) precipitation from oxygenated, Fe-rich water (iron formations), (b) hydrothermal extraction and crystal growth.

The Galileo Near Infrared Mapping Spectrometer was used to investigate the distribution and properties of sulfur dioxide over the surface of Io, and qualitative results for the anti-jove hemisphere are presented here.