References of "Loicq, Jerôme"
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See detailOUFTI-Next: the second cubesat of the university of Liège
Werner, Xavier ULiege; Habraken, Serge ULiege; Kerschen, Gaëtan ULiege et al

in Advances in the Astronautical Sciences (in press)

the ULiège selected the concept of an earth observation 3U CubeSat and corresponding ground segment to produce images in the mid-wave infrared (MWIR), dedicated to measure the hydric stress of vegetation ... [more ▼]

the ULiège selected the concept of an earth observation 3U CubeSat and corresponding ground segment to produce images in the mid-wave infrared (MWIR), dedicated to measure the hydric stress of vegetation. This monitoring would allow farmers to provide optimal irrigation to their crops and thus will lead to spare drinkable water. [less ▲]

Detailed reference viewed: 114 (26 ULiège)
See detailPhotonic management using opal-like crystals in perovskite solar cells
Lobet, Michaël ULiege; Piron, Pierre ULiege; Dewalque, Jennifer ULiege et al

Conference (2019, May 22)

Perovskite solar cells recently showed a tremendous interest among the photovoltaic community. However, little is known on the effect of light management inside PV architectures. We compare structured and ... [more ▼]

Perovskite solar cells recently showed a tremendous interest among the photovoltaic community. However, little is known on the effect of light management inside PV architectures. We compare structured and unstructured absorbing layers in order to enhance the integrated quantum efficiency. The photo-active layer is made of monolayer, bilayer or trilayer of perovskite spheres inside a TiO2 matrix. The excitation of guided resonances via Fano resonances inside the absorbing spheres enhances the integrated quantum efficiency and enables a photonic gain as high as 6.4%. Influence of sphere's radius, incident angle and incident polarization on the absorbing properties are also reported. [less ▲]

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See detailOpal-like CH3NH3PbI3 perovskite solar cells : effect of the 3D structuration on the conversion efficiency
Dewalque, Jennifer ULiege; Daem, Nathan ULiege; Spronck, Gilles ULiege et al

Poster (2019, May 13)

In this work, the 3D structuration of perovskite films is studied in order to highlight the effect of a periodic porous structure on the optical properties of the films (light harvesting, optical ... [more ▼]

In this work, the 3D structuration of perovskite films is studied in order to highlight the effect of a periodic porous structure on the optical properties of the films (light harvesting, optical coloration, semi-transparency…) and on the PV efficiency, in comparison with dense perovskite films usually used in planar solar cells configuration. The opal-like perovskite scaffold is obtained from templating fabrication method, with polystyrene beads as structuring agent. Five PS bead diameters are studied: 300 nm, 540 nm, 810 nm, 1.0 µm and 2.1 µm, to highlight the effect of the PS bead diameter on the optical properties of the films and on the PV efficiency. PbI2/CH3NH3I 0.7M in DMSO leads to the most covering, homogeneous and overlayer-free porous films. The PV efficiency of the corresponding cells increases with the bead diameter. A significant improvement in the PV conversion efficiency is observed thanks to the 3D structuration compared to a dense reference, due to the improvement of charge separation at the Spiro-OMeTAD/perovskite interface and thus to the reduction of charge recombination. In addition, CH3NH3PbI3 porous films prepared with 810 nm, 1000 nm and 2100 nm PS bead diameter respectively, are coloured, which is very interesting for building-integrated applications (BIPV). [less ▲]

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See detailCharacterizing the atmosphere of Proxima b with a space-based mid-infrared nulling interferometer
Defrere, Denis ULiege; Léger, A.; Absil, Olivier ULiege et al

in Proceedings of SPIE: The International Society for Optical Engineering (2018, July 09), 10701

Proxima b is our nearest potentially rocky exoplanet and represents a formidable opportunity for exoplanet science and possibly astrobiology. With an angular separation of only 35 mas (or 0.05 AU) from ... [more ▼]

Proxima b is our nearest potentially rocky exoplanet and represents a formidable opportunity for exoplanet science and possibly astrobiology. With an angular separation of only 35 mas (or 0.05 AU) from its host star, Proxima b is however hardly observable with current imaging telescopes and future space-based coronagraphs. One way to separate the photons of the planet from those of its host star is to use an interferometer that can easily resolve such spatial scales. In addition, its proximity to Earth and its favorable contrast ratio compared with its host M dwarf (approximately 10-5 at 10 microns) makes it an ideal target for a space-based nulling interferometer with relatively small apertures. In this paper, we present the motivation for observing this planet in the mid-infrared (5-20 microns) and the corresponding technological challenges. Then, we describe the concept of a space-based infrared interferometer with relatively small (<1m in diameter) apertures that can measure key details of Proxima b, such as its size, temperature, climate structure, as well as the presence of important atmospheric molecules such as H2O, CO2, O3, and CH4. Finally, we illustrate the concept by showing realistic observations using synthetic spectra of Proxima b computed with coupled climate chemistry models. © 2018 SPIE. [less ▲]

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See detailNƎSIE: a fiber-fed near-infrared spectrograph for TIGRE telescope
Kintziger, Christian ULiege; Rauw, Grégor ULiege; Desselle, Richard ULiege et al

in Evans, Christopher; Simard, Luc; Takami, Hideki (Eds.) Proceedings Volume 10702, Ground-based and Airborne Instrumentation for Astronomy VII (2018, July 06)

Our contribution intends to present the obtained performances of the NƎSIE instrument, a new near-infrared fiber-fed spectrograph developed at the University of Liège. This instrument was developed ... [more ▼]

Our contribution intends to present the obtained performances of the NƎSIE instrument, a new near-infrared fiber-fed spectrograph developed at the University of Liège. This instrument was developed, aligned and tested at the Centre Spatial de Liège and first light was achieved in October 2017. This paper will go through the alignment process and optical performance verification to eventually introduce the first light observations. The final location of NƎSIE will be the TIGRE telescope located in La Luz, Mexico. The observational data provided by this instrument will help several research groups from the University of Liège to study massive stars. In particularly, evolution models will be improved through the comparison of the collected spectra with theoretical models. This collaboration will therefore contribute to a better understanding of massive stars and the mechanisms that take place within these extraordinary objects. [less ▲]

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See detailLight-harvesting capabilities of dielectric sphere multilayers
Baron, Damien ULiege; Dewalque, Jennifer ULiege; Henrist, Catherine ULiege et al

in Proceedings of SPIE: The International Society for Optical Engineering (2018, March), 10541

Self-assembled synthetic opals are suitable for integration into solution-processed thin film solar cells. In this work, finite-difference time-domain simulations are carried out to tailor optical ... [more ▼]

Self-assembled synthetic opals are suitable for integration into solution-processed thin film solar cells. In this work, finite-difference time-domain simulations are carried out to tailor optical properties of monolayer and multilayers of semiconductor spheres to trap light when these structures are incorporated into thin film solar cells. In particular, architectures in which spheres are filled with a photoactive material and embedded in a lower refractive index medium are examined. Based on spectra and field intensity maps, this study demonstrates that opal-like photonic crystals obtained from colloidal templates and filled with light-absorbing material can significantly harvest light by exploiting photonic band resonances. [less ▲]

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See detailOpal-like photoanodes with photonic effects in macroporous perovskite solar cells
Dewalque, Jennifer ULiege; Baron, Damien ULiege; Spronck, Gilles ULiege et al

Poster (2018, February 28)

Organic-inorganic metal halide perovskite compounds, used either in mesoscopic or planar solar cells architectures, have allowed preparing highly efficient solid-state devices (>20%). In mesoscopic solar ... [more ▼]

Organic-inorganic metal halide perovskite compounds, used either in mesoscopic or planar solar cells architectures, have allowed preparing highly efficient solid-state devices (>20%). In mesoscopic solar cells, a mesoporous TiO2 scaffold is incorporated into the cells. However, because of the small pore size compared to the wavelengths of visible light, the scaffold barely scatters light. In this work, we propose to design periodically structured TiO2 scaffold from colloidal crystal templating fabrication method. Polystyrene beads with diameters comparable to visible light wavelengths are used as structuring agent. The resulting opal-like photonic structure will strongly interact with light and increase light harvesting. The photoanode microstructure is characterized by scanning electron microscopy (SEM) and X-Ray diffraction (XRD). In parallel, light interaction is modeled in order to find the best compromise in terms of photonic architecture. Sunlight absorption by the solar cells is presented and discussed with dependency of pore sizes and number of opal-like layers. [less ▲]

Detailed reference viewed: 113 (34 ULiège)
See detailA NEW TRIFOCAL DESIGN
Gatinel, Damien; Loicq, Jerôme ULiege

Conference (2017, October 06)

Purpose: Contributions of IOL biomaterial (Abbe #) and diffractive pattern topography on LCA of various types of multifocal IOLs. Methods: The LCAs associated with the different focal points of ... [more ▼]

Purpose: Contributions of IOL biomaterial (Abbe #) and diffractive pattern topography on LCA of various types of multifocal IOLs. Methods: The LCAs associated with the different focal points of diffractive hydrophobic – made of aromatic and/or aliphatic materials – and hydrophilic multifocal IOLs were experimentally determined on an optical bench in RGB conditions (650, 546 and 480 nm). The effects of Abbe number and of the topography of the different diffractive profiles were evaluated. Based on wavelength–dependent MTF through-focus curves, polychromatic behavior of multifocal IOLs was assessed. Results: LCA amplitudes and signs were different for each of the focal points. While far vision LCA was of negative sign and appeared to be controlled by the material Abbe number, the diffractive LCA for near and intermediate visions was independent of IOL material. The diffractive pattern characteristics, which control the closer distance powers, prove to be pivotal in fine-tuning the LCA related to these near and intermediate foci. Conclusions: Diffractive multifocal IOLs show chromatic aberrations with are controlled by the biomaterial Abbe number for its refractive component on the one hand, and by the topography of the diffractive pattern for the second component on the other hand. [less ▲]

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See detailLongitudinal Chromatic Aberration discussion on diffractive intraocular lenses
Loicq, Jerôme ULiege; Gatinel, Damien

Conference (2017, October 06)

Diffractive multifocal IOLs show chromatic aberration especially along the axis (LCA-longitudinal Chromatic aberration) but also out of the optical axis. These chromatic aberrations are the results of the ... [more ▼]

Diffractive multifocal IOLs show chromatic aberration especially along the axis (LCA-longitudinal Chromatic aberration) but also out of the optical axis. These chromatic aberrations are the results of the refractive chromatic properties of the lens, driven by refractive indexes involved into the light path and the diffractive profiles. Refractive effects are mainly controlled by the biomaterial Abbe number while diffractive effects are controlled by the topography of the diffractive pattern. The insertion of a multifocal diffractive lens after crystalline lens extraction may significantly modify the chromatic aberration of the pseudophakic eye. Chromatic aberrations are inducing vision losses due sharpness reduction of any object edges. The contrast sensitivity as much as the visual acuity are then reduced. This has been proven with measurements optical benches. Diffractive and refractive effects act in an opposite way and can in principle be compensated. However rules to creates an achromatic lens based on refractive-diffractive lens are quite complex because topology, dioptry , abbe number,… In this study, we will investigate the effect of wavelength on the through-focus modulation transfer function (MTF) and diffraction efficiency for different pupil apertures and different diffractive intraocular lenses. Pin-hole effect will also be discussed and addressed with the point of view of chromatic effect. [less ▲]

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See detailThe Far Ultra-Violet Imager on the Icon Mission
Mende, Stephen; Frey, Harald; Rider, Kodi et al

in Space Science Reviews (2017)

ICON Far UltraViolet (FUV) imager contributes to the ICON science objectives by providing remote sensing measurements of the daytime and nighttime atmosphere/ ionosphere. During sunlit atmospheric ... [more ▼]

ICON Far UltraViolet (FUV) imager contributes to the ICON science objectives by providing remote sensing measurements of the daytime and nighttime atmosphere/ ionosphere. During sunlit atmospheric conditions, ICON FUV images the limb altitude profile in the shortwave (SW) band at 135.6 nm and the longwave (LW) band at 157 nm perpendicular to the satellite motion to retrieve the atmospheric O/N2 ratio. In conditions of atmospheric darkness, ICON FUV measures the 135.6 nm recombination emission of O+ ions used to compute the nighttime ionospheric altitude distribution. ICON Far Ultra- Violet (FUV) imager is a Czerny–Turner design Spectrographic Imager with two exit slits and corresponding back imager cameras that produce two independent images in separate wavelength bands on two detectors. All observations will be processed as limb altitude profiles. In addition, the ionospheric 135.6 nm data will be processed as longitude and latitude spatial maps to obtain images of ion distributions around regions of equatorial spread F. The ICON FUV optic axis is pointed 20 degrees below local horizontal and has a steering mirror that allows the field of view to be steered up to 30 degrees forward and aft, to keep the local magnetic meridian in the field of view. The detectors are micro channel plate (MCP) intensified FUV tubes with the phosphor fiber-optically coupled to Charge Coupled Devices (CCDs). The dual stack MCP-s amplify the photoelectron signals to overcome the CCD noise and the rapidly scanned frames are co-added to digitally create 12-second integrated images. Digital on-board signal processing is used to compensate for geometric distortion and satellite motion and to achieve data compression. The instrument was originally aligned in visible light by using a special grating and visible cameras. Final alignment, functional and environmental testing and calibration were performed in a large vacuum chamber with a UV source. The test and calibration program showed that ICON FUV meets its design requirements and is ready to be launched on the ICON spacecraft. [less ▲]

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See detailCalibration and testing of wide-field UV instruments
Frey, Harald; Mende, Stephen; Loicq, Jerôme ULiege et al

in Journal of Geophysical Research. Space Physics (2017), 122

As with all optical systems the calibration of wide-field ultraviolet (UV) systems includes three main areas: sensitivity, imaging quality, and imaging capability. The one thing that makes UV calibrations ... [more ▼]

As with all optical systems the calibration of wide-field ultraviolet (UV) systems includes three main areas: sensitivity, imaging quality, and imaging capability. The one thing that makes UV calibrations difficult is the need for working in vacuum substantially extending the required time and effort compared to visible systems. In theory a ray tracing and characterization of each individual component of the optical system (mirrors, windows, and grating) should provide the transmission efficiency of the combined system. However, potentially unknown effects (contamination, misalignment, and measurement errors) can make the final error too large and unacceptable for most applications. Therefore, it is desirable to test and measure the optical properties of the whole system in vacuum and compare the overall response to the response of a calibrated photon detector. A proper comparison then allows the quantification of individual sources of uncertainty and ensures that the whole instrument performance is within acceptable tolerances or pinpoints which parts fail to meet requirements. Based on the experience with the IMAGE Spectrographic Imager, the Wide-band Imaging Camera, and the ICON Far Ultraviolet instruments, we discuss the steps and procedures for the proper radiometric sensitivity and passband calibration, spot size, imaging distortions, flatfield, and field of view determination. [less ▲]

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See detailInverse opal photoanodes: preparation and optical properties
Dewalque, Jennifer ULiege; Spronck, Gilles ULiege; Baron, Damien ULiege et al

Conference (2017, March 01)

Perovskite compounds, used either in mesoscopic or planar solar cells, have allowed preparing highly efficient solid-state devices (>20%). In this study, we propose to design photoanodes with photonic ... [more ▼]

Perovskite compounds, used either in mesoscopic or planar solar cells, have allowed preparing highly efficient solid-state devices (>20%). In this study, we propose to design photoanodes with photonic structure in order to modulate light interaction. The periodic structure of porosity could add specific optical properties likely to increase light harvesting and reduce reflexion losses. Besides, current efficiencies reported for mesoscopic perovskite solar cells using an inorganic porous scaffold are slightly lower than those reported for planar perovskite cells mainly due to issues in perovskite infiltration. The control of the porous network architecture in terms of pore organization, size and connectivity could overcome this limitation. TiO2/perovskite and perovskite-only photoanodes with an inverse opal porous structure are prepared from templating techniques, using polystyrene beads as structuring agent. The photoanode microstructure is further characterized by scanning electron microscopy (SEM) and X-Ray diffraction (XRD). In parallel, light interaction is modeled in order to find the best compromise in terms of photonic architecture (pore size, organization, thickness…). [less ▲]

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See detailPhotonic photoanode for macroporous perovskite solar cells
Baron, Damien ULiege; Dewalque, Jennifer ULiege; Henrist, Catherine ULiege et al

Poster (2017, March 01)

Organic-inorganic metal halide perovskite solar cells (PSCs) have reached power conversion efficiencies over 20%. Two archetypal PSC architectures are reported in the literature: mesoporous and planar ... [more ▼]

Organic-inorganic metal halide perovskite solar cells (PSCs) have reached power conversion efficiencies over 20%. Two archetypal PSC architectures are reported in the literature: mesoporous and planar PSCs. In the former one, a mesoporous TiO2 scaffold is incorporated into the cell. Because sizes of the mesopores are typically small compared to wavelengths of visible light, the scaffold barely scatters light. In this work, we propose to periodically structure a porous TiO2 scaffold incorporating pores with diameters comparable to wavelengths of visible light thanks to the use of colloidal crystal templating fabrication method. The resulting TiO2 scaffold filled with perovskite will constitute an opal-like photonic crystal incorporated in the solar cell, which will strongly interact with light. Through Finite Difference Time Domain (FDTD) simulations, we demonstrate that the photonic crystal induces resonances that can be exploited to modulate light harvesting in the macroporous TiO2 layer. Sunlight absorption by the PSC will be presented and discussed with dependency of pore sizes and number of opal layers. [less ▲]

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See detailConception of a near-infrared spectrometer for ground-based observations of massive stars
Kintziger, Christian ULiege; Desselle, Richard ULiege; Loicq, Jerôme ULiege et al

in Journal of Astronomical Telescopes, Instruments, and Systems (2017), 3(1), 015002

In our contribution, we outline the different steps in the design of a fiber-fed spectrographic instrument for stellar astrophysics. Starting from the derivation of theoretical relationships from the ... [more ▼]

In our contribution, we outline the different steps in the design of a fiber-fed spectrographic instrument for stellar astrophysics. Starting from the derivation of theoretical relationships from the scientific requirements and telescope characteristics, the entire optical design of the spectrograph is presented. Specific optical elements, such as a toroidal lens, are introduced to improve the instrument’s efficiency. Then the verification of predicted optical performances is investigated through optical analyses, such as resolution checking. [less ▲]

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See detailTRIFOCAL INTRAOCULAR LENS WITH EXTENDED RANGE OF VISION AND CORRECTION OF LONGITUDINAL CHROMATIC ABERRATION
Pagnoulle, Christophe; Redzovic, Suad; Voisin, Laure et al

Patent (2017)

The present invention relates to an intraocular lens, and in particular to an intraocular lens with three focal points and a diffractive profile on an anterior or posterior face. This lens provides ... [more ▼]

The present invention relates to an intraocular lens, and in particular to an intraocular lens with three focal points and a diffractive profile on an anterior or posterior face. This lens provides extended range of vision (EROV) from far to near distance and reduces linear chromatic aberration (LCA). [less ▲]

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See detailA 100 M GROUND RESOLUTION GLOBAL DAILY COVERAGE EARTH OBSERVATION MISSION
Loicq, Jerôme ULiege; Clermont, Lionel ULiege; Dierckx, Wouter et al

in Proceedings of SPIE: The International Society for Optical Engineering (2017), Proc. of SPIE Vol. 10563

PROBA-V has been successfully launched on 7th May 2013 and is providing a global monitoring in the continuity of the SPOT-VEGETATION mission. The progress in terms of ground resolution between Spot VGT ... [more ▼]

PROBA-V has been successfully launched on 7th May 2013 and is providing a global monitoring in the continuity of the SPOT-VEGETATION mission. The progress in terms of ground resolution between Spot VGT and PROBA-V is a factor 3 (1 km to 1/3 km ground resolution product). The User Community requirements for the next generation of global monitoring are a 100 m ground resolution product. This means an additional factor 3 improvement, but in a short time frame (5 years). After success of the PROBA-V mission, the Belgian Science Policy (BELSPO) initiates a PROBA-V Successor feasibility study. This study was undertaken by VITO and CSL to identify potential tracks to achieve a follow-on mission which is expected to be relevant for the User Community. The mission analyses for each of these tracks was evaluated. Today the PROBA-V mission lifetime is expected to expire by mid of 2018. Since the interest for global land monitoring is expected to continue in the future, this study proposes mission requirements and a shortlist of optimal mission scenarios for a follow-on mission in this short time frame. The goal of such a new PROBA-V mission is clear: it should ensure the data continuity of global vegetation monitoring, while taking the opportunity to further improve the data quality. Data continuity is essential for understanding long term trends of land use that may affect the global equilibrium of the planet (in the context of scarcity for land or food, natural disasters, climate change). As for added value, a fine example is the improvement of spatial resolution when comparing PROBA-V with the spatial resolution in SPOT-VEGETATION products. An improvement in spatial resolution towards a full 100m product is considered by the user community as the main target for a PROBA-V follow-on mission. [less ▲]

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See detailWaveguide solar concentrator design with spectrally separated light
Michel, Céline ULiege; Blain, Pascal ULiege; Clermont, Lionel ULiege et al

in Solar Energy (2017), 157

In this article, we propose a new solar concentrator based on spectral splitting of sunlight. Spectral splitting has the objective to collect different spectra onto spectrally adapted solar cells for a ... [more ▼]

In this article, we propose a new solar concentrator based on spectral splitting of sunlight. Spectral splitting has the objective to collect different spectra onto spectrally adapted solar cells for a more efficient use of the Sun’s spectrum. Its combination with solar concentration makes an alternative to classical technologies. The proposed concentrator is composed of a diffractive/refractive optical element that spectrally splits and focuses the light onto a waveguide. The light is then conducted by total internal reflection towards the two specific solar cells. The optical concept and optimization of each element is presented in this paper. An adaptation for dye sensitized solar cells is performed. A geometrical factor around 5× is reached. Finally, theoretical optical efficiency, the manufacturing process and experimental testing with a collimated Sun simulator are presented. [less ▲]

Detailed reference viewed: 70 (17 ULiège)
See detailClinically relevant optical properties of three types of intraocular lenses
Gatinel, Damien; Loicq, Jerôme ULiege

Conference (2016, September)

Purpose: To experimentally compare the optical performance of three types of hydrophobic intraocular lenses (IOLs): extended depth of focus (TECNIS Symfony), bifocal (TECNIS ZMB00), and trifocal ... [more ▼]

Purpose: To experimentally compare the optical performance of three types of hydrophobic intraocular lenses (IOLs): extended depth of focus (TECNIS Symfony), bifocal (TECNIS ZMB00), and trifocal (FineVision GFree). Setting: Rothschild Foundation Paris, France - Liege Space Center Liège, Belgique Methods: Surface topography was analyzed by optical microscopy. Modulation transfer function (MTF) and spherical aberrations were determined on optical bench for variable pupil apertures and with two cornea models (0 µm and +0.28 µm). United States Air Force target imaging was analyzed for different focal points (near, intermediate, and far). Point spread function (PSF) and halos were quantified and compared. Results: All lenses presented step-like optic topography. For a pupil size of = 3 mm, distinctive MTF peaks were observed for all lenses: two peaks for the extended depth of focus and bifocal lenses with +1.75 and +4.00 diopters (D) addition, respectively, and three peaks for the trifocal lens with +1.75 and +3.50 addition for intermediate and near vision, respectively. The extended depth of focus and bifocal lens had slightly higher MTF at best focus with the +0.28 µm cornea model than with the 0 µm model, whereas the trifocal lens was likely to be more independent of the corneal spherical aberrations. Conclusions: Each lens appears to rely on light diffraction for optical performance, presenting halos with comparable intensities. For small pupil apertures, the MTF peaks for the far and intermediate focal distances of the trifocal and extended depth of focus lenses overlap, but the trifocal lens presented an additional MTF peak for the near focal points. [less ▲]

Detailed reference viewed: 58 (1 ULiège)
See detailRefractive and diffractive contribution of linear chromatic aberration (LCA) on depth-of-focus with trifocal intraocular lenses (IOLs)
Loicq, Jerôme ULiege; Gatinel, Damien

Poster (2016, September)

Purpose: To investigate the refractive and diffractive contribution of LCA on depth of focus extension of trifocal IOLs in polychromatic light conditions Setting: University of Liège, Belgium; Fondation ... [more ▼]

Purpose: To investigate the refractive and diffractive contribution of LCA on depth of focus extension of trifocal IOLs in polychromatic light conditions Setting: University of Liège, Belgium; Fondation Ophtalmologique A. de Rothschild, Paris Methods: The LCAs associated with the three focal points of hydrophobic and hydrophilic diffractive FineVision trifocal IOLs (PhysIOL SA, Liège, Belgium), were simulated in an Arizona eye model and experimentally measured on an optical bench at 480, 546 and 650 nm. The effect of Abbe number and aperture on different IOL materials was also evaluated. Based on wavelength–dependent MTF through-focus curves and PSF properties, polychromatic behavior of the trifocal IOLs was assessed under mesopic and photopic conditions. Results: LCA amplitude and sign were different for each of the trifocal IOL focal points. The diffractive LCA for near and intermediate was independent of IOL material (GFree versus hydrophilic acrylic, 26%), while far vision LCA appeared to be controlled by the material Abbe number. Under polychromatic conditions, the LCA contributed to depth of focus extension with different types of lens material, providing maximal visual acuity under white light conditions at all distances. Conclusions: Diffractive trifocal IOLs show chromatic aberrations with an increase in depth of focus under polychromatic light. This effect likely contributes to the extended range of vision. [less ▲]

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See detailConception of a near-IR spectrometer for ground-based observations of massive stars
Kintziger, Christian ULiege; Desselle, Richard ULiege; Loicq, Jerôme ULiege et al

in Proc. SPIE Volume 9908 Ground-based and Airborne Instrumentation for Astronomy VI (2016, August 09)

In our contribution, we outline the different steps in the design of a fiber-fed spectrographic instrument that intends to observe massive stars. Starting from the derivation of theoretical relationships ... [more ▼]

In our contribution, we outline the different steps in the design of a fiber-fed spectrographic instrument that intends to observe massive stars. Starting from the derivation of theoretical relationships from the scientific requirements and telescope characteristics, the entire optical design of the spectrograph is presented. Specific optical elements, such as a toroidal lens, are introduced to improve the instrument’s performances. Then, the verification of predicted optical performances is investigated through optical analyses such as resolution checking. Eventually, the star positioning system onto the central fiber core is explained. [less ▲]

Detailed reference viewed: 59 (15 ULiège)