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See detailSecond harmonic generation from tyrosine containing peptides
Nasir, Mehmet Nail ULg; Bergmann, Emeric; Benichou, Emmanuel et al

in Proceedings of SPIE (2013), 8817

The Second Harmonic Generation (SHG) response from Tyrosine-containing peptides at the air-water interface is presented. First, the quadratic hyperpolarizability of the aromatic amino acid Tyrosine ... [more ▼]

The Second Harmonic Generation (SHG) response from Tyrosine-containing peptides at the air-water interface is presented. First, the quadratic hyperpolarizability of the aromatic amino acid Tyrosine obtained by Hyper Rayleigh Scattering is reported, demonstrating its potentiality as an endogenous molecular probe for SHG studies. Then, the single Tyrosine antimicrobial peptide Mycosubtilin is monitored at the air-water interface and compared to another peptide, Surfactin, lacking a Tyrosine residue. Adsorption kinetics and polarization analysis of the SHG intensity for the peptide monolayers clearly demonstrate that the SHG response from Mycosubtilin arises from Tyrosine. Besides, it confirms that indeed Tyrosine can be targeted as an endogenous molecular probe. [less ▲]

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See detailSecond harmonic hotspots at the edges of the unit cells in G-shaped gold nanostructures
Valev, VK; Osley, EJ; De Clercq, B et al

in Proceedings of SPIE (2012), 8424

We report our latest results on second harmonic generation (SHG) microscopy from arrays of G-shaped chiral gold nanostructures. The nanostructures are arranged in unit cells composed of four Gs, each ... [more ▼]

We report our latest results on second harmonic generation (SHG) microscopy from arrays of G-shaped chiral gold nanostructures. The nanostructures are arranged in unit cells composed of four Gs, each rotated at 90° with respect to its neighbors. As it has already been demonstrated, for linearly polarized light, these unit cells yield a pattern of four SHG hotspots. However, upon increasing the pitch of the nanostructured arrays, extra hotspots can be observed at the edges of the unit cells. While the origin of these extra hotspots remains to be elucidated, their position indicates a relationship to coupling behavior between the unit cells. [less ▲]

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See detailRobustness of the scanning second harmonic generation microscopy technique for characterization of hotspot patterns in plasmonic nanomaterials
Valev, VK; De Clercq, B; Zheng, X et al

in Proceedings of SPIE (2012), 8424

Scanning second harmonic generation (SHG) microscopy is becoming an important tool for characterizing nanopatterned metal surfaces and mapping plasmonic local field enhancements. Here we study G-shaped ... [more ▼]

Scanning second harmonic generation (SHG) microscopy is becoming an important tool for characterizing nanopatterned metal surfaces and mapping plasmonic local field enhancements. Here we study G-shaped and mirror-G-shaped gold nanostructures and test the robustness of the experimental results versus the direction of scanning, the numerical aperture of the objective, the magnification, and the size of the laser spot on the sample. We find that none of these parameters has a significant influence on the experimental results. [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 detailThe Lyman-alpha telescope of the extreme ultraviolet imager on Solar Orbiter
Schühle, Udo; Halain, Jean-Philippe ULg; Meining, Stefan et al

in Proceedings of SPIE (2011), 8148

On the Solar Orbiter mission, the Extreme Ultraviolet Imager (EUI) set of filtergraph-telescopes consists of two high-resolution imagers (HRI) and one dual-band full Sun imager (FSI) that will provide ... [more ▼]

On the Solar Orbiter mission, the Extreme Ultraviolet Imager (EUI) set of filtergraph-telescopes consists of two high-resolution imagers (HRI) and one dual-band full Sun imager (FSI) that will provide images of the solar atmosphere in the extreme ultraviolet and in the Lyman-α line of hydrogen at 121.6 nm. The Lyman-α HRI, in particular, will provide imaging of the upper chromospheres/lower transition region of the Sun at unprecedented high cadence and at an angular resolution of one 1″ (corresponding to a spatial resolution of 200 km at perihelion). For vacuum-ultraviolet imaging of the Sun the main requirements for the instrumentation are high resolution, high cadence, and large dynamic range. We present here the novel solutions of the instrument design and show in detail the predicted performance of this telescope. We describe in detail how the high throughput and spectral purity at 121.6 nm is achieved. The technical solutions include multilayer coatings of the telescope mirrors for high reflectance at 121.6 nm, combined with interference filters and a multichannel-plate intensified CMOS active pixel camera. We make use of the design flexibilities of this camera to optimize the dynamic range in the focal plane. [less ▲]

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See detailUsing a Savart plate in optical metrology
Blain, Pascal ULg; Michel, Fabrice ULg; Renotte, Yvon ULg et al

in Proceedings of SPIE (2010, August), 7791

Non-contact optical measurement methods are essential tools in many industrial and research domains. A family of new non-contact optical measurement methods based on the polarization states splitting ... [more ▼]

Non-contact optical measurement methods are essential tools in many industrial and research domains. A family of new non-contact optical measurement methods based on the polarization states splitting technique and monochromatic light projection as a way to overcome ambient lighting for in-situ measurement has been developed1,2. Recent works3 on a birefringent element, a Savart plate, allow to build a more flexible and robust interferometer. This interferometer is a multipurpose metrological device. On one hand, the interferometer can be set in front of a CCD camera. This optical measurement system is called a shearography interferometer and allows to measure micro displacement between two states of the studied object under coherent lighting. On the other hand, by producing and shifting multiple sinusoidal Young’s interference patterns with this interferometer, and using a CCD camera, it is possible to build a 3D structured light profilometer. After giving the behavior of the Savart plate, an overview of the two devices will be given as well as their specifications and some applications. [less ▲]

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See detailFirst light of SWAP on-board PROBA2
Halain, Jean-Philippe ULg; Defise, Jean-Marc ULg; Rochus, Pierre ULg et al

in Proceedings of SPIE (2010), 7732

The SWAP telescope (Sun Watcher using Active Pixel System detector and Image Processing) is an instrument launched on 2nd November 2009 on-board the ESA PROBA2 technological mission. SWAP is a space ... [more ▼]

The SWAP telescope (Sun Watcher using Active Pixel System detector and Image Processing) is an instrument launched on 2nd November 2009 on-board the ESA PROBA2 technological mission. SWAP is a space weather sentinel from a low Earth orbit, providing images at 174 nm of the solar corona. The instrument concept has been adapted to the PROBA2 mini-satellite requirements (compactness, low power electronics and a-thermal opto-mechanical system). It also takes advantage of the platform pointing agility, on-board processor, Packetwire interface and autonomous operations. The key component of SWAP is a radiation resistant CMOS-APS detector combined with onboard compression and data prioritization. SWAP has been developed and qualified at the Centre Spatial de Liège (CSL) and calibrated at the PTB-Bessy facility. After launch, SWAP has provided its first images on 14th November 2009 and started its nominal, scientific phase in February 2010, after 3 months of platform and payload commissioning. This paper summarizes the latest SWAP developments and qualifications, and presents the first light results. [less ▲]

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See detailA gas micromechanical sensor based on surface plasmon resonance
Hastanin, Juriy ULg; Habraken, Serge ULg; Renotte, Yvon ULg et al

in Proceedings of SPIE (2008, October 02), 7116

We will present a new concept related to the micromechanical sensors for detecting the presence and concentration of chemical substances and/or biological organisms. A bi-dimensional array of micro ... [more ▼]

We will present a new concept related to the micromechanical sensors for detecting the presence and concentration of chemical substances and/or biological organisms. A bi-dimensional array of micro-cantilever coated by different types of sensing layer enables to identify a characteristic chemical composition of the gas in real-time mode. The selective molecular absorption by cantilever sensing layer will produce cantilever bending proportional to the concentration of molecules. To increase the gas sensor sensitivity, the SPR phenomenon is used for cantilever deflection monitoring. [less ▲]

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See detailThe JWST MIRI Double-Prism, Design and Science Drivers
Fisher, Sebastian; Rossi, Laurence ULg; Renotte, Etienne ULg et al

in Proceedings of SPIE (2008, July 12), 7010

We present how it is achieved to mount a double prism in the filter wheel of MIRIM - the imager of JWST’s Mid Infrared Instrument. In order to cope with the extreme conditions of the prisms’ surroundings ... [more ▼]

We present how it is achieved to mount a double prism in the filter wheel of MIRIM - the imager of JWST’s Mid Infrared Instrument. In order to cope with the extreme conditions of the prisms’ surroundings, the low resolution double prism assembly (LRSDPA) design makes high demands on manufacturing accuracy. The design and the manufacturing of the mechanical parts are presented here, while ’Manufacturing and verification of ZnS and Ge prisms for the JWST MIRI imager’ are described in a second paper [1]. We also give insights on the astronomical possibilities of a sensitive MIR spectrometer. Low resolution prism spectroscopy in the wavelength range from 5-10 microns will allow to spectroscopically determine redshifts of objects close to/at the re-ionization phase of the universe. [less ▲]

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See detailManufacturing and verification of ZnS and Ge prisms for the JWST MIRI imager
Rossi, Laurence ULg; Renotte, Etienne ULg; Plesseria, Jean-Yves ULg et al

in Proceedings of SPIE (2008, June 23), 7018

The JWST Mid-Infrared Instrument (MIRI) is designed to meet the JWST science requirements for mid-IR capabilities and includes an Imager MIRIM provided by CEA (France). A double-prism assembly (DPA ... [more ▼]

The JWST Mid-Infrared Instrument (MIRI) is designed to meet the JWST science requirements for mid-IR capabilities and includes an Imager MIRIM provided by CEA (France). A double-prism assembly (DPA) allows MIRIM to perform low-resolution spectroscopy. The MIRIM DPA shall meet a number of challenging requirements in terms of optical and mechanical constraints, especially severe optical tolerances, limited envelope and very high vibration loads. <br />The University of Cologne (Germany) and the Centre Spatial de Liege (Belgium) are responsible for design, manufacturing, integration, and testing of the prism assembly. A companion paper (Fischer et al. 2008) is presenting the science drivers and mechanical design of the DPA, while this paper is focusing on optical manufacturing and overall verification processes. <br />The first part of this paper describes the manufacturing of Zinc-sulphide and Germanium prisms and techniques to ensure an accurate positioning of the prisms in their holder. (1) The delicate manufacturing of Ge and ZnS materials and (2) the severe specifications on the bearing and optical surfaces flatness and the tolerance on the prism optical angles make this process innovating. The specifications verification is carried out using mechanical and optical measurements; the implemented techniques are described in this paper. <br />The second part concerns the qualification program of the double-prism assembly, including the prisms, the holder and the prisms anti-reflective coatings qualification. Both predictions and actual test results are shown. [less ▲]

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See detailHigh density resolution synchrotron radiation based X-ray microtomography (SR mu CT) for quantitative 3D-morphometrics in zoological sciences
Nickel, Michael; Hammel, Jörg U; Herzen, Julia et al

in Proceedings of SPIE (2008), 7078

Zoological sciences widely rely on morphological data to reconstruct and understand body structures of animals. The best suitable methods like tomography allow for a direct representation of 3D-structures ... [more ▼]

Zoological sciences widely rely on morphological data to reconstruct and understand body structures of animals. The best suitable methods like tomography allow for a direct representation of 3D-structures. In recent years, synchrotron radiation based X-ray microtomography (SR mu CT) placed high resolutions to the disposal of morphologists. With the development of highly brilliant and collimated third generation synchrotron sources, phase contrast SR mu CT became widely available. A number of scientific contributions stressed the superiority of phase contrast over absorption contrast. However, here we demonstrate the power of high density resolution methods based on absorption-contrast SR mu CT for quantitative 3D-measurements of tissues and other delicate bio-structures in zoological sciences. We used beamline BW2 at DORIS III (DESY, Hamburg, Germany) to perform microtomography on tissue and mineral skeletons of marine sponges (Porifera) which were shock frozen and/or fixed in a glutamate osmium tetroxide solution, followed by critical point drying. High density resolution tomographic reconstructions allowed running quantitative 3D-image analyses in Matlab and ImageJ. By applying contrast and shape rule based algorithms we semi-automatically extracted and measured sponge body structures like mineral spicules, elements of the canal system or tissue structures. This lead to a better understanding of sponge biology: from skeleton functional morphology and internal water flow regimes to body contractility. Our high density resolution based quantitative approach can be applied to a wide variety of biological structures. However, two prerequisites apply: (1) maximum density resolution is necessary; (2) edge effects as seen for example in phase outline contrast SR mu CT must not be present. As a consequence, to allow biological sciences to fully exploit the power of SR mu CT further increase of density resolution in absorption contrast methods is desirable. [less ▲]

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See detailQuantum imaging with uncorrelated single photon sources
Bastin, Thierry ULg

in Proceedings of SPIE (2008)

We propose a technique to obtain sub-wavelength resolution using photons from uncorrelated single photon sources. The method employs N photons of wavelength λ spontaneously emitted from N atoms and ... [more ▼]

We propose a technique to obtain sub-wavelength resolution using photons from uncorrelated single photon sources. The method employs N photons of wavelength λ spontaneously emitted from N atoms and subsequently detected by N detectors. We demonstrate that for certain detector positions the N-th order correlation function as a function of the first detector position is a pure sinusoidal oscillation with a fringe spacing of λ/N and a contrast of 100%. The result corresponds to an N-fold increase in resolution compared to classical microscopy. Our technique is also capable of imaging a distinct physical object with sub-Rayleigh resolution. [less ▲]

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See detailNegative refraction: theory and application to thin metal layer superlens
Lecler, Sylvain; Frere, Benjamin; Habraken, Serge ULg et al

in Proceedings of SPIE (2008), 6987

The main concepts dealing with negative refraction are clarified in order to understand if a high conductive metal layer thinner than the wavelength can really be considered as a metamaterial with a ... [more ▼]

The main concepts dealing with negative refraction are clarified in order to understand if a high conductive metal layer thinner than the wavelength can really be considered as a metamaterial with a negative refraction index. The theoretical method to find the direction of phase velocity is clearly explained. The use of the causality principle is presented. We discuss why the negative refractive metamaterial has to be regarded as a dispersive one. Discussions are illustrated by means of FDTD simulations. The superlens application is presented. We explain why it is not obvious to consider a thin metal layer as a negative refractive material. [less ▲]

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See detailA far infrared/terahertz micromechanical sensor based on surface plasmons resonance
Hastanin, Juriy ULg; Renotte, Yvon ULg; Fleury-Frenette, Karl ULg et al

in Proceedings of SPIE (2008), 7113

This paper describes a new concept related to the bolometric micromechanical sensors for detecting far IR and THz radiation. We believe that this concept permits a low cost and ease of fabrication of ... [more ▼]

This paper describes a new concept related to the bolometric micromechanical sensors for detecting far IR and THz radiation. We believe that this concept permits a low cost and ease of fabrication of large bi-dimensional array of sensors with an enhanced signal-to-noise ratio. The micromechanical sensor comprises a thermo-sensitive bi-material (multimaterial) micro-cantilever beam with a selective absorber dedicated to far IR and THz radiation energy, and optical readout system based on surface plasmon resonance for detecting the bending of the micro-cantilever element. To increase the radiation detector sensitivity, the SPR phenomenon is used for cantilever deflection monitoring. [less ▲]

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See detailAntireflective subwavelength patterning of IR optics
Vandormael, Denis; Habraken, Serge ULg; Loicq, Jerôme ULg et al

in Proceedings of SPIE (2006), 6395

Thermal infrared (IR) lenses require efficient anti-reflection coating. Moth-eye (or egg-box) 2D subwavelength gratings have demonstrated their ability to reach a very high transmission for a wide ... [more ▼]

Thermal infrared (IR) lenses require efficient anti-reflection coating. Moth-eye (or egg-box) 2D subwavelength gratings have demonstrated their ability to reach a very high transmission for a wide wavelength and angular range. The use in thermal IR is simplified by the lower resolution for lithographic technology, compared to visible waveband. However, deeper structures must be engraved and lithography must be adapted to IR materials. In order to be cost-effective, the patterning must be produced by replication techniques, such as embossing. Our laboratory is now experimenting hot embossing of moth-eye patterns in chalcogenide substrates. In this paper, theoretical analysis, micro-lithographic technology and manufacturing processes are detailed. [less ▲]

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See detailHuman-Visual-System-Based Fusion of Multimodality 3D Neuroimagery using Brain-Shift-Compensating Finite-Element-Based Deformable Models
Verly, Jacques ULg; Vigneron, Lara; Petitjean, Nicolas et al

in Proceedings of SPIE (2003, February), 5029

Our goal is to fuse multimodality imagery to enhance image-guided neurosurgery. Images that need to be fused must be registered. Registration becomes a challenge when the imaged object deforms between the ... [more ▼]

Our goal is to fuse multimodality imagery to enhance image-guided neurosurgery. Images that need to be fused must be registered. Registration becomes a challenge when the imaged object deforms between the times the images to be fused are taken. This is the case when “brain-shift” occurs. We begin by describing our strategy for nonrigid registration via finite-element methods. Then, we independently discuss an image fusion strategy based on a model of the human visual system. We illustrate the operation of many components of the registration system and the operation of the fusion system. [less ▲]

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See detailHolographic Filter applied to LCD projector for improvement of laser pointer presentation
Habraken, Serge ULg; Moreau, Vincent; Vandormael, Denis et al

in Proceedings of Spie (2000), 3951

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