References of "Loicq, Jerôme"
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See detailLarge white organic light-emitting diode lighting panel on metal foils
Guaino, Philippe; Mazeri, Fabrizo; Hofmann, Michael et al

in Journal of Photonics for Energy [=JPE] (2011), 1

Large-area top-emitting PIN structure (highly p- and n- type doped transport layers for electrons and holes and an undoped emitter layer)–organic light-emitting diode (OLED) on advanced metal foils were ... [more ▼]

Large-area top-emitting PIN structure (highly p- and n- type doped transport layers for electrons and holes and an undoped emitter layer)–organic light-emitting diode (OLED) on advanced metal foils were fabricated for lighting applications. ArcelorMittal has developed a new surface treatment on metal foils, suitable for roll-to-roll production and dedicated to large-area device integration. Both monochromatic and white devices are realized on advanced metal foils. Power efficiencies at 1000 cd/m2 of >70 lm/W (green), moreover, power efficiency of white devices of >22 lm/W are achieved. Furthermore, first large-area 60 × 60 cm white OLED sources on metal foils are presented. [less ▲]

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See detailExperimental validation of opto-thermo-elastic modeling in OOFELIE Multiphysics
Mazzoli, Alexandra ULg; Saint-Georges, Philippe; Orban, Anne ULg et al

in SPIE, Optical Systems Design (Marseille 5-8 septembre 2011) (2011)

The objective of this work is to demonstrate the correlation between a simple laboratory test bench case and the predictions of the Oofelie MultiPhysics software in order to deduce modelling guidelines ... [more ▼]

The objective of this work is to demonstrate the correlation between a simple laboratory test bench case and the predictions of the Oofelie MultiPhysics software in order to deduce modelling guidelines and improvements. For that purpose two optical systems have been analysed. The first one is a spherical lens fixed in an aluminium barrel, which is the simplest structure found in an optomechanical system. In this study, material characteristics are assumed to be well known: BK7 and aluminium have been retained. Temperature variations between 0 and +60°C from ambient have been applied to the samples. The second system is a YAG laser bar heated by means of a dedicated oven. For the two test benches thermo-elastic distortions have been measured using a Fizeau interferometer. This sensor measures wavefront error in the range of 20 nm to 1 μm without physical contact with the optomechanical system. For the YAG bar birefringence and polarization measurements have also been performed using a polarimetric bench. The tests results have been compared to the predictions obtained by Oofelie MultiPhysics which is a multiphysics toolkit treating coupled problems of optics, mechanics, thermal physics, electricity, electromagnetism, acoustics and hydrodynamics. From this comparison modelling guidelines have been issued with the aim of improving the accuracy of computed thermo-elastic distortions and their impact on the optical performances. [less ▲]

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See detailContinuous Solar Simulator for Concentrator Photovoltaic Systems
Thibert, Tanguy ULg; Hellin, Marie-Laure ULg; Loicq, Jerôme ULg et al

in Proceedings of the 25th European Photovoltaic Solar Energy Conference (2010, September)

A continuous solar simulator for measuring performance of concentrator photovoltaic (CPV) systems is presented. The illumination system is based on a Xenon lamp, a homogenizer rod, shaping optics and a ... [more ▼]

A continuous solar simulator for measuring performance of concentrator photovoltaic (CPV) systems is presented. The illumination system is based on a Xenon lamp, a homogenizer rod, shaping optics and a 30cm diameter collimator. The design optimises the reproduction of the characteristics of direct solar illumination: 32’ divergence, high spatial homogeneity, sun-like spectral distribution, with a maximum intensity of 250W/m². It accommodates pass-band and attenuation filters to tune the beam output. It operates in continuous mode, allowing to investigate CPV thermal aspects as well. The present paper addresses the concept design of the solar simulator and associated performance results. [less ▲]

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See detailAchromatization of solar concentrator using diffractive optics
Languy, Fabian ULg; Lenaerts, Cedric ULg; Loicq, Jerôme ULg et al

Poster (2009)

Photovoltaic energy suffers from payback time. High solar concentration (above 500 suns) is a very interesting way to reduce production cost. The use of lenses allows more flexibility to make light flux ... [more ▼]

Photovoltaic energy suffers from payback time. High solar concentration (above 500 suns) is a very interesting way to reduce production cost. The use of lenses allows more flexibility to make light flux more uniform. In addition lenses are less prone to errors of manufacture and can be easily duplicated. Unfortunately, optical materials are very dependent on the wavelength which causes important chromatic aberrations. One can think about achromatic doublets but doublets are thick, heavy and require exotic glasses which make them expensive. During the conference, I would like to present an innovative way to achromatize solar concentrators using hybrid (refractive/diffractive) lenses. Indeed, an hybrid lens is as thin as a Fresnel lens and is made in only one glass. But diffractive lenses suffer from limited broadband diffraction efficiency due to spurious orders. To overcome the lake of efficiency we are investigating the use of multi-layer diffractive optical element. This technique allows to achieve an efficiency greater than 97% over the full visible spectrum using only three components (e.g. two optical elements + air). [less ▲]

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See detailAchromatization of solar concentrator thanks to diffractive optics
Languy, Fabian ULg; Lenaerts, Cedric ULg; Loicq, Jerôme ULg et al

Conference (2009)

Refractive solar concentrators suffer from important chromatic aberration. To enhance solar cell performance and increase the concentrating ratio, we propose an hybrid (diffractive/refractive) lens which ... [more ▼]

Refractive solar concentrators suffer from important chromatic aberration. To enhance solar cell performance and increase the concentrating ratio, we propose an hybrid (diffractive/refractive) lens which allows a more uniform flux density and an achromatized (in the sense of achromatic doublet) illumination of the cell. To solve the problem of high diffraction efficiency, we turn to multilayer diffractive lenses to have broadband high diffraction efficiency optimized on solar spectrum. Rigorous coupled wave analysis simulations were performed in order to check the validity of scalar theory, they led to a new order of magnitude for the ratio period/wavelength which has been found to be around 100 in place of 10. [less ▲]

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See detailHybrid wetting state on micro-waffle textures
Caps, Hervé ULg; Vandormael, Denis; Loicq, Jerôme ULg et al

in Europhysics Letters (2009), 88

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See detailMicro-technology for space mission
Loicq, Jerôme ULg

Conference (2007, October 03)

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See detailAdaptation of photorefractive holographic camera for observation of micro-mechanical structures
Georges, Marc ULg; Thizy, Cédric ULg; Loicq, Jerôme ULg et al

in Hesselink, L.; Feinberg, J. (Eds.) Controlling Light with Light: Photorefractive Effects, Photosensitivity, Fiber Gratings, Photonic Materials and More (PR07) (2007, October)

The photorefractive holographic camera initially working on large scattering objects has been adapted to observe centimetric to micrometric objects. Application on micro-mechanical systems is presented

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See detailFresnel rhombs as achromatic phase shifters for infrared nulling interferometry
Mawet, D.; Hanot, Charles ULg; Lenaers, C. et al

in Optics Express (2007), 15

We propose a new family of achromatic phase shifters for infrared nulling interferometry. These key optical components can be seen as optimized Fresnel rhombs, using the total internal reflection ... [more ▼]

We propose a new family of achromatic phase shifters for infrared nulling interferometry. These key optical components can be seen as optimized Fresnel rhombs, using the total internal reflection phenomenon, modulated or not. The total internal reflection indeed comes with a phase shift between the polarization components of the incident light. We propose a solution to implement this vectorial phase shift between interferometer arms to provide the destructive interference process needed to disentangle highly contrasted objects from one another. We also show that, modulating the index transition at the total internal reflection interface allows compensating for the intrinsic material dispersion in order to make the subsequent phase shift achromatic over especially broad bands. The modulation can be induced by a thin film of a well-chosen material or a subwavelength grating whose structural parameters are thoroughly optimized. We present results from theoretical simulations! together with preliminary fabrication outcomes and measurements for a prototype in Zinc Selenide. [less ▲]

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See detailFresnel rhombs as achromatic phase shifters for infrared nulling interferometry: first experimental results
Hanot, Charles ULg; Mawet, D.; Loicq, Jerôme ULg et al

in Coulter, Daniel R (Ed.) "Techniques and Instrumentation for Detection of Exoplanets III" Proceedings of the SPIE, Volume 6693, Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (2007, September 01)

One of the most critical units of nulling interferometers is the Achromatic Phase Shifter. The concept we propose here is based on optimized Fresnel rhombs, using the total internal reflection phenomenon ... [more ▼]

One of the most critical units of nulling interferometers is the Achromatic Phase Shifter. The concept we propose here is based on optimized Fresnel rhombs, using the total internal reflection phenomenon, modulated or not. The total internal reflection induces a phase shift between the polarization components of the incident light. We present the principles, the current status of the prototype manufacturing and testing operations, as well as preliminary experiments on a ZnSe Fresnel rhomb in the visible that have led to a first error source assessment study. Thanks to these first experimental results using a simple polarimeter arrangement, we have identified the bulk scattering as being the main error source. Fortunately, we have experimentally verified that the scattering can be mitigated using spatial filters and does not decrease the phase shifting capabilities of the ZnSe Fresnel rhomb. [less ▲]

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See detailThe annular groove phase mask coronagraph: an achromatic optical vortex
Mawet, D.; Riaud, Pierre ULg; Hanot, Charles ULg et al

in Coulter, Daniel R (Ed.) "Techniques and Instrumentation for Detection of Exoplanets III" Proceedings of the SPIE, Volume 6693, Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (2007, September 01)

The Annular Groove Phase Mask coronagraph (AGPM) is an intrinsically achromatic vectorial vortex. It consists of integrated subwavelength optical elements whose space-variant polarization properties can ... [more ▼]

The Annular Groove Phase Mask coronagraph (AGPM) is an intrinsically achromatic vectorial vortex. It consists of integrated subwavelength optical elements whose space-variant polarization properties can be engineered and optimized to synthesize one of the theoretically most efficient coronagraphs. This paper briefly recalls the principles of the AGPM, presents the benefit of its implementation inside a polarimetric differential imager, realistic numerical simulations assessing its performances, as well as the current status of the near-infrared and visible prototype manufacturing operations. [less ▲]

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See detailQuantitative accelerated life testing of MEMS accelerometers
Bazu, Marius; Gălăţeanu, Lucian; Ilian, Virgil Emil et al

in sensors (2007), 7(11), 2846

Quantitative Accelerated Life Testing (QALT) is a solution for assessing the reliability of Micro Electro Mechanical Systems (MEMS). A procedure for QALT is shown in this paper and an attempt to assess ... [more ▼]

Quantitative Accelerated Life Testing (QALT) is a solution for assessing the reliability of Micro Electro Mechanical Systems (MEMS). A procedure for QALT is shown in this paper and an attempt to assess the reliability level for a batch of MEMS accelerometers is reported. The testing plan is application-driven and contains combined tests: thermal (high temperature) and mechanical stress. Two variants of mechanical stress are used: vibration (at a fixed frequency) and tilting. Original equipment for testing at tilting and high temperature is used. Tilting is appropriate as application-driven stress, because the tilt movement is a natural environment for devices used for automotive and aerospace applications. Also, tilting is used by MEMS accelerometers for anti-theft systems. The test results demonstrated the excellent reliability of the studied devices, the failure rate in the “worst case” being smaller than 10-7h-1. [less ▲]

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See detailRELIABILITY ACCELERATED TESTING OF MEMS ACCCELEROMETERS
Bazu, Marius; Gălăţeanu, Lucian; Ilian, Virgil Emil et al

in IEEE Sensors Journal (2007), 1

An attempt to assess the reliability of a batch of MEMS accelerometers is presented. The testing plan is application oriented and contains combined tests: thermal and mechanical stresses (two variants ... [more ▼]

An attempt to assess the reliability of a batch of MEMS accelerometers is presented. The testing plan is application oriented and contains combined tests: thermal and mechanical stresses (two variants: vibration and tilting) were used. The results demonstrated the good reliability of the tested device, the failure rate being smaller than 6.10-8h-1. [less ▲]

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See detailSpectroscopy of the nonlinear refractive index of colloidal PbSe nanocrystals
Moreels, Iwan; Hens, Zeger; Kockaert, Pascal et al

in Applied Physics Letters (2006), 89

A spectroscopic study of the optical nonlinearity of PbSe colloidal solutions was performed with the Z-scan technique at wavelength intervals of 1200–1350 and 1540–1750 nm. While nonlinear absorption ... [more ▼]

A spectroscopic study of the optical nonlinearity of PbSe colloidal solutions was performed with the Z-scan technique at wavelength intervals of 1200–1350 and 1540–1750 nm. While nonlinear absorption remains below the detection threshold, the third order nonlinear refractive index n2 shows clear resonances, somewhat blueshifted relative to the exciton transitions in the absorbance spectrum. The occurrence of thermal effects is ruled out by time-resolved measurements. At 1.55 m, measured resonant n2 values exceed typuial blk semiconductor values by two orders of magnitude. At high optical intensity, the refractive index change saturates, indicating that statefilling lies at the origin of the observed effect. [less ▲]

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See detailThermo-optical properties of colloidal solutions of CdTe nanoparticles
Rosso, Vanessa ULg; Loicq, Jerôme ULg; Galstian, T. et al

in Optical Materials (2006), 28(8-9), 1041-1046

Colloidal solutions of CdTe nanoparticles have been prepared by the "electropulse" technique. The diameters of the CdTe nanoparticles range from 5 to 30 nm. The goal of this work is to study the formation ... [more ▼]

Colloidal solutions of CdTe nanoparticles have been prepared by the "electropulse" technique. The diameters of the CdTe nanoparticles range from 5 to 30 nm. The goal of this work is to study the formation and evolution of the induced thermo-refractive index with a long-term goal of forming a thermal lens. An induced thermo-refractive index occurs when the CdTe solutions are irradiated with a strong laser beam. The experimental approach is derived from the Z-scan technique, a technique which is very sensitive to refractive index modulation in a sample. Thermo-optical coefficients, such as the thermal diffusivity, D, the characteristic build-up time of the thermal lens, t(c), and the induced thermo-refractive index can be determined from dynamic Z-scan curves. The thermo-optical coefficients have been determined at different wavelengths, beam powers, and for different nanoparticles sizes. (C) 2005 Elsevier B.V. All rights reserved. [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 detailThe non-linear refractive index of colloidal PbSe nanocrystals:Spectroscopy and saturation behaviour
Moreels, Iwan; Kockaert, Pascal; Van Deun, Rick et al

in Journal of Luminescence (2006), 121

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See detailMoems Packaging for Harsh environments
Loicq, Jerôme ULg

Conference (2005, May 31)

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See detailOptical non-linearity in disperse red 1 dye-doped sol-gel
Rosso, Vanessa ULg; Loicq, Jerôme ULg; Renotte, Yvon ULg et al

in Journal of Non-Crystalline Solids (2004), 342(1-3), 140-145

A third-order non-linear optical effect, the optical Kerr effect, was studied in DR1-doped sol-gel using the Z-scan method which allows studying both processes of non-linear absorption and refraction. The ... [more ▼]

A third-order non-linear optical effect, the optical Kerr effect, was studied in DR1-doped sol-gel using the Z-scan method which allows studying both processes of non-linear absorption and refraction. The materials under study are sol-gel substrates, amorphous silica glasses doped by the azo-dye Disperse Red 1. Modifying the conditions of the sol-gel synthesis, in particular the pH of the catalytic medium, enabled us to vary the morphology of the sol-gel substrate. Non-linear effects of various amplitudes were observed in so-gel substrates of various porosities, involving different non-linear mechanisms. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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