References of "Fleury-Frenette, Karl"
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See detailA Thermal Detector
Fleury-Frenette, Karl ULg; Habraken, Serge ULg; Renotte, Yvon ULg et al

Patent (2013)

A first object of the invention is a radiation detector comprising an energy absorber (203), for absorbing incident radiation (RAD) and thus undergoing a temperature increase; and optical readout means ... [more ▼]

A first object of the invention is a radiation detector comprising an energy absorber (203), for absorbing incident radiation (RAD) and thus undergoing a temperature increase; and optical readout means, for detecting said temperature increase; wherein said optical readout means comprises input coupling means (202) for coupling a light beam (2011) to said energy absorber (203) by exciting surface plasmons resonance, a surface plasmons resonance condition being dependent on the energy absorber (203) temperature, and wherein said energy absorber (203) is separated from said input coupling means (202) by a dielectric layer (2032). A second object of the invention is a micromechanical sensor comprising: a micromechanical oscillator and optical readout means (202) for detecting a displacement of said micromechanical oscillator; wherein said optical readout means comprise input coupling means (202) for coupling a light beam (2011) to a conductive surface (2031) by exciting surface plasmons resonance, a surface plasmons resonance condition being dependent on the displacement of said micromechanical oscillator. [less ▲]

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See detailMeasurements of non-Rutherford cross sections for 4-15 MeV alpha particles on light elements from C to Si
Chene, Grégoire ULg; Mathis, François ULg; Fleury-Frenette, Karl ULg et al

Conference (2013, September)

These last years Ion Beam Analysis users show an interest in High Energy Alpha beams[1]. These beams can be used for on-site analysis by means of radioactive sources e.g. for space application but they ... [more ▼]

These last years Ion Beam Analysis users show an interest in High Energy Alpha beams[1]. These beams can be used for on-site analysis by means of radioactive sources e.g. for space application but they also offer a powerful combination of properties for the analysis of thick layers (about 10 to 20 µm). This kind of layers is often met in cultural heritage applications but can be also present on new materials. Contrary to this kind of materials where the principal information needed is the in-depth profiles as the sample are of known composition, for cultural heritage materials the combination of elemental analysis and their in-depth distribution is essential as the nature of the material is a-priori not known. In this perspective high energy alpha beams can produce really interesting results as their PIXE cross-sections increase from 6 MeV while the lower penetration of the beam (comparing to classical protons beams) allows to limit the analysis to the layer of interest. For the elemental in depth distribution we take advantage of the good mass separation of the alpha particles and the non-Rutherford phenomena allow the analysis even of light elements which are of great interest in cultural heritage problematic as far as the cross section are well tabulated. Using two IBA facilities (AGLAE in Paris and the HE-HR beam line of the cyclotron in Liège University[2]) we explored the backscattering cross section of numerous light elements (from C to Si) from 4 to 15 MeV in order to check the lack in the literature, to verify the deviation from Rutherford law and compare it to the existing theoretical models. We begin to measure the needed cross sections using thick target in case of smooth cross section and thin layers for exploring important variation of the cross section. [less ▲]

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See detailSubstrate Mode-Integrated SPR Sensor
Lenaerts, Cedric ULg; Vilcot, Jean-Pierre; Hastanin, Juriy ULg et al

in Plasmonics (2013), 8(2), 1203-1208

We present the design, implementation and characterisation of an integrated surface plasmon resonance (SPR) biosensor chip involving diffractive optical coupling elements avoiding the need of prism ... [more ▼]

We present the design, implementation and characterisation of an integrated surface plasmon resonance (SPR) biosensor chip involving diffractive optical coupling elements avoiding the need of prism coupling. The integrated sensor chip uses the angular interrogation principle and includes two diffraction gratings and the SPR sensing zone. The theoretical design is presented as well as the fabrication process. Experimental results (response of a reference water droplet and phosphate-buffered saline/water kinetic) are presented and compared with those obtained with the classical Kretschmann prism coupling setup. We believe that this prism-free architecture is perfectly suitable for low-cost and reproducible SPR biochemical sensor chips since the sensing zone can be functionalised as any other one [less ▲]

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See detailThe Solar Sail Material (SSM) Project : Results of Activities
Dalla Vedova, Florio; de Wilde, Don; Semprimoschnig, Christopher et al

in The Third International Symposium on Solar Sailing: Book of abstracts (2013, May 28)

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See detailCompact integrated surface plasmon resonance spectroscopic sensor platform with on-chip self-referencing
Hastanin, Juriy ULg; Fleury-Frenette, Karl ULg; Lenaerts, Cedric ULg et al

in Proceeding of the International Conference on Surface Plasmon Photonics (SPP6): Ottawa, Canada, May 2013 (2013, May)

We present the SPR_CD spectroscopic biosensor design experimentally investigated by our research group. The implemented sensor platform is dedicated to droplet biochemical analysis involving multichannel ... [more ▼]

We present the SPR_CD spectroscopic biosensor design experimentally investigated by our research group. The implemented sensor platform is dedicated to droplet biochemical analysis involving multichannel detection format. [less ▲]

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See detailScientific and Technological Payloads Aboard the B3LSat CubeSat of the QB50 Network
Dell'Elce, Lamberto ULg; Kerschen, Gaëtan ULg; Delabie, Tjorven et al

in Proceedings of the 2nd IAA Conference on University Satellite Missions and Cubesat Workshop (2013)

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See detailInnovative Surface Plasmon Resonance biosensing architectures
Desfours, Caroline; Piron, Pierre ULg; Habraken, Serge ULg et al

Conference (2012, December 11)

Surface Plasmons Resonance (SPR) architectures involving multi-wavelength interrogation are an attractive alternative for droplet biosensing. We present our results for in situ measurements of biological ... [more ▼]

Surface Plasmons Resonance (SPR) architectures involving multi-wavelength interrogation are an attractive alternative for droplet biosensing. We present our results for in situ measurements of biological molecules with a two-wavelength sensor and a SPR Coupler-Disperser spectroscopic sensor. [less ▲]

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See detailInnovative Surface Plasmon Resonance biosensing architectures
desfours, Caroline; Hastanin, Juriy ULg; Drucbert, Anne-Sophie et al

in International Conference on Fibre Optics and Photonics (2012, December)

Surface Plasmons Resonance (SPR) architectures involving multi-wavelength interrogation are an attractive alternative for droplet biosensing. We present our results for in situ measurements of biological ... [more ▼]

Surface Plasmons Resonance (SPR) architectures involving multi-wavelength interrogation are an attractive alternative for droplet biosensing. We present our results for in situ measurements of biological molecules with a two-wavelength sensor and a SPR Coupler- Disperser spectroscopic sensor. [less ▲]

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See detailIsolating the 130.4 nm and 135.6 nm emissions in Ganymede’s aurora using broadband optics
Molyneux, Philippa M; Grodent, Denis ULg; Bunce, Emma J et al

Conference (2012, September 27)

We discuss a technique for isolating the two main Far Ultraviolet emission lines in Ganymede’s aurora by adding flight proven transmission filters to a broad- band, wide-field imager design. We find that ... [more ▼]

We discuss a technique for isolating the two main Far Ultraviolet emission lines in Ganymede’s aurora by adding flight proven transmission filters to a broad- band, wide-field imager design. We find that the ra- tio of OI emissions at 135.6 nm and 130.4 nm can be recovered if the transmission of the filters and other optical elements are well known. This ratio allows constraints to be placed on the relative abundances of O atoms and O2 molecules within Ganymede’s at- mosphere, leading to more accurate models of atmo- spheric composition. [less ▲]

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See detailLaser thermoreflectance for semiconductor thin films metrology
Gailly, Patrick ULg; Hastanin, Juriy ULg; Duterte, Charles et al

in Wehrspohn, R. B., Gombert, A (Ed.) Photonics for Solar Energy Systems IV (2012, June)

We present a thermoreflectance-based metrology concept applied to compound semiconductor thin films off-line characterization in the solar cells scribing process. The presented thermoreflectance setup has ... [more ▼]

We present a thermoreflectance-based metrology concept applied to compound semiconductor thin films off-line characterization in the solar cells scribing process. The presented thermoreflectance setup has been used to evaluate the thermal diffusivity of thin CdTe films and to measure eventual changes in the thermal properties of 5 μm CdTe films ablated by nano and picosecond laser pulses. The temperature response of the CdTe thin film to the nanosecond heating pulse has been numerically investigated using the finite-difference time-domain (FDTD) method. The computational and experimental results have been compared. [less ▲]

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See detailMethod for manufacturing an improved optical layer of light emitting device with surface nano-micro texturation based on coherent electromagnetic radiation speckle lithography
Loicq, Jerôme ULg; Fleury-Frenette, Karl ULg; Vandormael, Denis

Patent (2012)

An object of the present invention is to provide a cheap, rapid, controlled, reproducible and polyvalent method for manufacturing a light emitting device with an internal source of light capable of ... [more ▼]

An object of the present invention is to provide a cheap, rapid, controlled, reproducible and polyvalent method for manufacturing a light emitting device with an internal source of light capable of achieving an enhancement in extraction efficiency. The invention proposes a method for manufacturing an optical layer for a light emitting device having an internal source of light and an optical layer separating the internal source of light and an external medium of light diffusion, wherein the method comprises the use of coherent electromagnetic radiation speckle lithography, such as laser speckle lithography, to make a nano/micro texturation on at least one surface of the optical layer [less ▲]

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See detailExperimental Results of Flat Fresnel Doublets made of PMMA and PC
Languy, Fabian ULg; Fleury-Frenette, Karl ULg; Lenaerts, Cedric ULg et al

Conference (2012, April)

To reduce the chromatic aberration lots of imaging systems like cameras and telescopes turn to achromatic doublets. On the other hand, to be cheaper, lighter and thinner, more and more systems like ... [more ▼]

To reduce the chromatic aberration lots of imaging systems like cameras and telescopes turn to achromatic doublets. On the other hand, to be cheaper, lighter and thinner, more and more systems like projectors and headlights use Fresnel lenses. To combine high performances and low cost, the use achromatic Fresnel doublets has been investigated. [less ▲]

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See detailJupiter system Ultraviolet Dynamics Explorer (JUDE), an instrument proposed for the ESA-JUICE mission
Grodent, Denis ULg; Bunce, Emma J.; Renotte, Etienne ULg et al

Report (2012)

In the proposal that follows we present a detailed concept for the science case, instrument requirements, technical design, calibration and operations, management structure, and financial plan for the ... [more ▼]

In the proposal that follows we present a detailed concept for the science case, instrument requirements, technical design, calibration and operations, management structure, and financial plan for the Jupiter system Ultraviolet Dynamics Experiment (JUDE), which will provide an outstanding solution to the UV instrumentation requirements for the JUICE mission. The JUDE instrument will represent a novel technical capability in UV instrumentation for planetary science, and will deliver the first true UV imaging capability beyond Earth orbit. The JUDE instrument design consists of two separate channels – the imaging channel (ImaC) and the spectrograph channel (SpeC), neither of which has any moving parts. This simple combination of two autonomous channels allows a true image and a spectrum at FUV wavelengths to be obtained simultaneously, allowing science goals to be realised which are not possible with a traditional scanning-slit imaging-spectrograph design The international consortium assembled to build the JUDE instrument is formed of two institutes from two European countries, and one from the United States. Prof. Denis Grodent (Université de Liège, Belgium) will act as the PI for the entire instrument team and the ULg/CSL team will provide a substantial hardware contribution to the instrument in the form of the optics, coatings, and Data Processing Unit (DPU). Dr Emma Bunce (University of Leicester, UK) will act as Co-PI for the instrument and the UoL team will supply the Micro-Channel Plate (MCP) detectors and read-out electronics. Prof. John Clarke (Co-I) of Boston University, USA will provide the grating element for the spectral channel of the instrument, in addition to instrument calibration activities. The science Co-Is are gathered from multiple institutes/nations including Belgium, UK, Germany, Italy, and the United States (see Part 1 for the full team list). Collectively, the team have decades of expertise in the areas of outer planet magnetospheres, planetary auroral and atmospheric emissions and surface UV observations from multiple platforms including Cassini UVIS, Juno UVS, Hubble Space Telescope, and numerous terrestrial missions. The team also have roles on non-UV instruments which will maximise the interpretation of the JUDE data. The two instrument channels are built on proven and robust technology with much flight heritage (e.g. Juno, Cassini, BepiColombo, IMAGE, ROSAT, Chandra, Voyager, Freja, DE-1, Swift). More specifically, the optics and focal plane detector proposed for the JUDE instrument are widely based on previous designs by CSL, at the ULg and UoL, for the FUV Spectro-Imager on the NASA IMAGE spacecraft, the UV Spectrograph on the NASA Juno mission to Jupiter, and the ROSAT Wide Field Camera. The data return from the instrument will greatly benefit the European and international science communities in planetary and terrestrial sciences, and the knowledge obtained will be generally applicable to broader astrophysics disciplines (e.g. extrasolar planetary physics). In answering the UV science objectives for the JUICE mission the JUDE instrument will clearly address the ESA Cosmic Vision Themes 1: What are the conditions for planet formation and the emergence of life? and 2: How does the Solar System work? The JUDE images (in particular) provide a clear path towards a high-level related programme of education and public outreach which the JUDE team are well equipped and keen to exploit. The JUDE instrument will contribute to all of the UV-related science objectives of JUICE, plus additional science objectives not listed in the Science Requirements Matrix. - At Ganymede and other moons (Europa and Callisto) JUDE will contribute directly to breakthroughs in the following scientific areas: 1) the characterisation of local environment, specifically through the first investigation of the morphology and variation of Ganymede’s aurora. A clear understanding of the auroral and atmospheric emissions at Ganymede will provide vital information on their formation mechanisms and will contribute to studies of the interaction of the Ganymede magnetosphere with Jupiter’s magnetosphere; 2) the first detailed observations of the satellites’ atmospheric (exosphere/ionosphere) composition and structure through measurements of their atmospheric emission and absorption spectra during multiple stellar occultation opportunities; and 3) the study of the satellites surface composition using surface reflectance measurements. The measurements at UV wavelengths are essential because they allow the study of the relationship between the satellites’ surface weathering, their atmospheres and the external environment which is mainly affected by the surrounding Jovian magnetosphere. By carefully studying processes at the surface and in the satellites’ atmospheres together, JUDE will provide the information required to distinguish between two classes of compositional heterogeneities at the satellites’ surfaces: 1) heterogeneities that arise from interaction with the external environment; 2) heterogeneities that arise from dynamical interaction with the subsurface. - With respect to Jupiter, JUDE will: 1) provide “state of the art” measurements of the Jovian atmospheric dynamics and transport through high temporal and spatial resolution auroral imaging; 2) allow a new understanding of the Jovian magnetosphere as a fast rotator through interpretation of the Jovian aurora as direct evidence for the 3D magnetosphere dynamics – a view which is continuously available in the planet’s upper atmosphere (independent of the spacecraft location within the magnetosphere); 3) investigate the magnetosphere as a giant accelerator through observations of the field-aligned current systems responsible for acceleration of electrons (and production of aurora); 4) discover the plasma sources and sinks of the moons through auroral imaging of the moon footprints in Jupiter’s atmosphere as a witness of the electromagnetic interactions taking place; 5) obtain new information on Jupiter’s atmospheric structure and composition through multiple stellar occultation opportunities. In addition, JUDE will make remote observations of the Io torus emissions and will provide the first in situ observation of the variability of the torus, over the lifetime of the mission, providing important information about the internal activity of the moon. JUDE offers a unique opportunity to obtain the first concurrent datasets of the different coupled elements of the Jupiter system: Io's atmosphere, aurora, the plasma torus, the Jovian plasma sheet and the Jovian aurora. The JUDE imaging and spectral channels are both designed to capture FUV lines from sulphur ions in the Io plasma torus. Finally, JUDE’s remote sensing capability offers an exciting opportunity to discover the Europa “plume” activity that may be present, through limb observations during flybys and from more distant observing locations. The Ganymede-focused and moon related science objectives will be addressed in the Ganymede orbit phase and during the multiple moon flybys, whilst the Jupiter science will be predominantly achieved during the Jupiter Equatorial Phases and during the high-inclination phase. The JUDE UV imager and spectrograph will produce discovery level science at Ganymede and the first true 2D UV images from Jupiter orbit. The exceptional JUICE trajectory affords many opportunities for breakthrough science discoveries in accordance with the SciRD; in addition to those, it provides unprecedented opportunities to directly witness the electromagnetic connection between Ganymede and Jupiter by making the first simultaneous UV observations of the respective atmospheres within the JUDE field-of-view. This is possible as a direct consequence of the JUDE true imaging capability. To successfully meet the science requirements outlined above, the JUDE ImaC has a spatial resolution of 20 arcsec over a circular field-of-view with 6˚ diameter, which allows a 100 km spatial resolution on Jupiter from Ganymede orbital distances (and 20 m resolution on Ganymede from 200 km, for example). JUDE’s ImaC mirrors and detector window will be covered with multilayer coatings which efficiently select a narrow bandpass from 130 to 143 nm, to allow measurements of the faint Oxygen lines at 130.4 nm and 135.6 nm in Ganymede’s (and other moon’s) atmosphere. This bandpass also allows observations of the SIV lines (between 140.5 and 142.4 nm) emitted within the Io plasma torus and in Io’s atmosphere. The bright Jovian emissions will also be suppressed within this bandpass which will necessarily limit the count rate to an acceptable level. The Ly-α line at 122 nm will be largely excluded as will the reflected sunlight longward of 150 nm. The sensitivity of the ImaC is 50 Rayleigh (at 3-sigma). The SpeC has a spectral resolution of 0.5 nm in order to meet the requirements of the SciRD, and has a field-of-view which is a 6˚ x 0.1˚ slit co-aligned with, and centred on, the ImaC circular field-of-view. The lower wavelength of the SpeC bandpass is set to ~110 nm in order to include the bright Ly-α line (useful to study the H corona) in a region of reduced transmission. The upper wavelength limit, ~195 nm, is such that transmission is slowly decreasing in the 180-195 nm spectral region, allowing measurements of the moon’s albedos beyond 165 nm, as well as the detection of compounds such as CO2, SO2, O2, O3, H2CO3 and H2O2 by comparing JUDE reflectance spectra to those obtained in laboratory studies. FUV emission lines from S and O are also observable within the bandpass and B-type stars emitting within this waveband will allow occultation experiments to be performed, to determine the composition and structure of the moon’s atmospheres and the detection of a possible Europa plume. The same is true for the Jovian atmosphere for which attenuation by H2 and hydrocarbons allows determination of the atmospheric structure. The sensitivity of the SpeC is 10 R/nm (at 3-sigma). The JUDE instrument channels: ImaC and the co-aligned SpeC, are both operating within the 110–195 nm range. Each channel has independent optics and detector elements, providing a level of redundancy such that loss of either imager or spectrograph does not constitute an entire loss of science. In contrast to more conventional (e.g. scanning or pushbroom) imaging spectrographs, JUDE can provide high time resolution (<1 second) high throughput images over a wide field of view (6° diameter) with no time variation across the field – a capability which is critical in gaining a better understanding of the complex dynamical processes taking place in the Jovian magnetosphere. The primary optic in each channel is a multilayer-coated mirror operating at normal incidence, with flight heritage in the form of the scan mirror in the Ultraviolet Spectrograph (UVS) now en-route to Jupiter onboard JUNO. The imaging channel uses a secondary mirror to of a similar type to focus the image onto the focal plane detector, while in the spectrograph channel, the secondary is a spherical, holographic grating. The spectrograph design is simple, with heritage in airglow spectrographs flown on terrestrial UV missions, and the Imaging UV Spectrograph for MAVEN. The grating element is produced by Jobin-Yvon, who have produced diffraction gratings for major missions including SOHO and HST. Each channel includes an identical microchannel plate (MCP) detector with the robust, radiation-tolerant performance required for a mission in the formidable environment of Jupiter. Such detectors are well proven, having flown on many missions including ROSAT (UoL heritage). They have also operated in the vicinity of Jupiter, in the focal plane of the UV spectrograph onboard the Voyager probes. The detector readout is a new type of capacitive division image charge readout (C-DIR; invented by Dr Jon Lapington) which offers, simultaneously, high spatial resolution and high count rate performance. Adaptive signal processing capabilities allow JUDE to accommodate the very wide dynamic range expected, from observations of Jupiter’s auroral ovals which emit with intensities of mega Rayleighs, to the weak (few tens of Rayleigh) emissions found at Ganymede. The readout structure is simple and robust, and has already been demonstrated in laboratory trials, while the electronics chain has its heritage in particle physics detectors, and has therefore been designed with radiation tolerance as a primary consideration. Pre-launch and in-flight calibrations will be implemented to assure that the JUDE data are suitable for quantitative scientific analysis. The proposed JUDE configuration successfully meets the scientific objectives of the JUICE mission. Our decision to implement an imaging channel instead of covering the MUV waveband increases the whole mission’s scientific output while remaining compliant with the MPDD. Due to its high-temporal resolution read-out system, JUDE is capable of producing volumes of data that are incompatible with the limited telemetry allocated to the UV instrument, even after a modest compression factor is applied. We therefore have proposed a mode of operation (the JUDE reference mode) which takes 1 minute snapshots over an observation opportunity (for example during a flyby sequence). Using this reference mode, and taking the maximum count rate estimates for the various targets, we find that the JUDE data volume is compliant with the tight allocation for the UV instrumentation of 40 GBytes/year The JUDE design presented in this proposal is above the mass allocation. We believe that all components of our design are necessary to reach the scientific goals of JUICE mission and that any major changes (such as the descope of a channel) will be at the considerable expense of the expected science return. However, further optimisation will be performed during the Phase A to bring JUDE into the allocated mass envelope while compromising its scientific return only slightly. We propose an efficient management structure with clearly delineated responsibilities. The Principal Investigator, Prof. Denis Grodent (Be) will take on the responsibilities as specified in the JUICE payload Announcement of Opportunity, supported closely by the Co-PI Dr Emma Bunce (UK) and by the team of Co-Investigators. The contribution of each country is represented by lead Co-Investigators: Prof. John Clarke (Boston University), Dr. Candy Hansen (PSI), and Dr Xianzhe Jia (University of Michigan), and Dr Nigel Bannister (UK) as CoI and Instrument Scientist (see Figure 1 below). The philosophy has been to assign well-defined tasks to each institute with an overall project manager to coordinate the efforts. The Consortium Project Manager (Etienne Renotte, CSL) will execute the managerial tasks relevant to the instrument development. The Product and Quality Assurance management will be implemented by all hardware contributors. Each consortium institute has a local project manager for their respective work packages, reporting to the Consortium Project Manager. The outreach potential of JUDE’s instantaneous wide field images is enormous. The potential PhD students of 2030 who we hope to educate and inspire with JUDE images and spectra are currently 3 years old; their supervisors are in secondary school. The team regards the educational aspects of the instrument and data as particularly important, and we plan a comprehensive JUDE/JUICE programme of outreach to schools and to the public, as part of the project and one which will be initiated upon selection. The national funding agency of Belgium serves as the Lead Funding Agency (LFA) for the JUDE instrument. The letters of endorsement from Belgium and United Kingdom are included in this proposal. Although the agencies endorse their respective national contributions, funding will be secured after the selection of the instrument proposal, according to the usual procedure. [less ▲]

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See detailIntegrated prism-free coupled surface plasmon resonance biochemical sensor
Lenaerts, Cedric ULg; Hastanin, Juriy ULg; Pinchemel, Bernard et al

in Proceedings of SPIE (2012), 8424

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See detailExperimental investigation of droplet biosensing by multi-wavelength plasmonic
Desfours, Caroline ULg; Habraken, Serge ULg; Hastanin, Juriy ULg et al

in Proceedings of SPIE Vol. 8234 : Plasmonics in Biology and Medicine IX (2012)

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See detailRipple topography and roughness evolution on surface of polycrystalline gold and silver thin films under low energy Ar-ion beam sputtering
Gailly, Patrick ULg; Petermann, Claire; Tihon, Pierre et al

in Applied Surface Science (2012), 258

Metallic thin films of gold and silver have been sputtered by argon ions at low energy in the framework of technological applications including nanostructuring and ion beam figuring. Ion beam sputtering ... [more ▼]

Metallic thin films of gold and silver have been sputtered by argon ions at low energy in the framework of technological applications including nanostructuring and ion beam figuring. Ion beam sputtering at high angle of incidence usually leads to spontaneous formation of periodic structures on the target surface, commonly referred as ripples. In this work, ripples dimensions and roughness evolution have been studied as function of the angle of incidence (0–80°), ion beam energy (400 – 1200 eV) and ion flux. The ripple wave vector direction was always observed perpendicular to the ion beam direction for both materials, in agreement with theoretical predictions for the investigated experimental conditions. The decrease of ripple wavelength with energy and ion flux shows the dominance of thermal diffusion as smoothing mechanism. Moreover, three regimes for roughness evolution on gold and silver films have been observed as function of the angle of incidence for sputtering at 650 eV, with a minimum roughness achieved around 45° and 60° for gold and silver, respectively. [less ▲]

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See detailOLED Light extraction improvement with surface nano-micro texturation based on speckle lithography.
Loicq, Jerôme ULg; Fleury-Frenette, Karl ULg; Viville, Pascal et al

in Physiscs and Optics of OLEDs (2012)

Part of the light rays generated within a luminescent medium with a higher refractive index than that of the exit medium, typically air, undergo total internal reflection phenomenon (TIR); these rays will ... [more ▼]

Part of the light rays generated within a luminescent medium with a higher refractive index than that of the exit medium, typically air, undergo total internal reflection phenomenon (TIR); these rays will be trapped and guided into the emissive material and will not be extracted out of an OLED device for instance. Trapped light is reabsorbed and eventually converted into heat that will be detrimental to the device performance and lifetime. The amount of trapped energy is highly dependent on the values of the refractive indices involved in the multilayer stack constituting the light emitting device. The amount of trapped energy can be extensive and can even reach as much as 75% in certain cases. Solutions to improve the outcoupling efficiency are therefore attractive. In this paper we propose to use laser speckle to produce a random surface with controlled parameters to enhance the OLED outcoupling. A laser speckle pattern is transferred onto a photoresist which will be subsequently converted into a surface relief profile. The optical setup parameters drive the properties of such surface and thus the outcoupling properties. The resulting surface has a quasi-random shape which could be assimilated to a corrugated surface. We will show that these typical surfaces exhibit light extraction enhancement properties. The generated pattern is then transferred onto the exit interfaces of the emitting device. An extraction improvement close to a factor 3 is measured. We finally discuss a practical case for which the laser speckle shape is applied to texture the surface of encapsulating cover glasses in a top-emitting OLED on steel substrates. [less ▲]

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See detailThe Solar Sail Materials (SSM) project – Status of activities
Della Vedova, Florio; Henrion, Didier; Leipold, Manfred et al

in Advances in Space Research (2011), 48(11), 1922-1926

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See detailUltrathin EUV Filters Testing and Characterization under High Flux (13 SC) for Solar Orbiter EUI Instrument
Jacques, Lionel ULg; Halain, Jean-Philippe ULg; Rossi, Laurence ULg et al

Conference (2011, October 07)

The test setup and characterization parameters of ultrathin EUV filters under high solar flux are presented. These 150nm thick aluminium filters are used at the entrance of the Extreme Ultraviolet Imager ... [more ▼]

The test setup and characterization parameters of ultrathin EUV filters under high solar flux are presented. These 150nm thick aluminium filters are used at the entrance of the Extreme Ultraviolet Imager (EUI) payload, which is developed at the Centre Spatial de Liège for the Solar Orbiter ESA M-class mission. The solar flux that they shall have to withstand will be as high as 13 solar constants when the spacecraft reach its 0.28AU perihelion. A specific design based on additional ribs has therefore been developed to enhance the thermal behaviour and heat evacuation while preserving its optical properties. It is essential to assess the design performances under the Solar Orbiter high solar flux. Therefore, thermal vacuum test under 13 solar constants will be performed. The filters temperature profiles will be measured during the tests through infrared imaging. A thermal correlation of the test will then be performed to deduce the filters actual thermal properties to be used in the global instrument geometrical and thermal mathematical models. [less ▲]

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See detailFlat Fresnel doublets made of PMMA and PC: combining low cost production and very high concentration ratio for CPV
Languy, Fabian ULg; Fleury-Frenette, Karl ULg; Lenaerts, Cedric ULg et al

in Optics Express (2011), 19(S3), 280-294

The linear chromatic aberration (LCA) of several combinations of polycarbonates (PCs) and poly (methyl methacrylates) (PMMAs) as singlet, hybrid (refractive/diffractive) lenses and doublets operating with ... [more ▼]

The linear chromatic aberration (LCA) of several combinations of polycarbonates (PCs) and poly (methyl methacrylates) (PMMAs) as singlet, hybrid (refractive/diffractive) lenses and doublets operating with wavelengths between 380 and 1600 nm – corresponding to a typical zone of interest of concentrated photovoltaics (CPV) – are compared. Those comparisons show that the maximum theoretical concentration factor for singlets is limited to about 1000 × at normal incidence and that hybrid lenses and refractive doublets present a smaller LCA increasing the concentration factor up to 5000 × and 2 × 106 respectively. A new achromatization equation more useful than the Abbé equation is also presented. Finally we determined the ideal position of the focal point as a function of the LCA and the geometric concentration which maximizes the flux on the solar cell. [less ▲]

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