Papers by Heidi Ottevaere
Design of a miniaturized integrated spectrometer for spectral tissue sensing
Optical Modelling and Design IV, 2016
Detailed kinetic performance analysis of micromachined radially elongated pillar array columns for liquid chromatography
Journal of chromatography. A, Jan 12, 2016
The individual factors that determine the kinetic performance (B- and C-term band broadening and ... more The individual factors that determine the kinetic performance (B- and C-term band broadening and bed permeability Kv) of radially elongated pillar (REP) columns are studied. To this end, columns with REPs having 4 different aspect ratios (AR=9, 12, 15, 20) were characterized experimentally and by means of numerical simulations. A tortuosity and retention based plate height equation was established, enabling a good global fit for all studied conditions. The B-term plate height contribution appears to decrease with a factor equaling the square of the flow path tortuosity τ. Going from AR=12 to AR=20 (τ=5.7 and τ=9.0 respectively), this resulted in a shift in plate height expressed in axial coordinates from Hmin=0.42μm to Hmin=0.25 for non-retained conditions and from H=0.77μm to H=0.57μm for a component with k=1.0. The obtained parameters were combined to predict optimal time-efficiency combinations for all possible channel lengths. This revealed an efficiency limit of N=10(7) plates ...
Performances of optical multi-chip-module interconnects: comparing guided-wave and free-space pathways
J Opt, 1999
We simulate and compare optical transmission efficiencies, throughputs and interconnection length... more We simulate and compare optical transmission efficiencies, throughputs and interconnection lengths of free-space and POF-based guided-wave multi-chip-module optical interconnection demonstrators for different types of microcavity emitters.
Membrane deflection in a flat membrane microcontactor: Experimental study of spacer features
Journal of Membrane Science, 2016
<title>AFM benchmark for the profile characterisation of subwavelength diffractive elements within the EC Network of Excellence on Micro-Optics (NEMO)</title>
Optical Micro- and Nanometrology in Microsystems Technology, 2006
The round robin "measurement of subwavelength diffractive elements" tackles the metrolo... more The round robin "measurement of subwavelength diffractive elements" tackles the metrology problems related to the measurement of diffraction gratings by AFM. It aims at quantifying the absolute precision and the uncertainty of the measurement considering some features of such structures like the depth, the period, the fill factor and the shape of the profile. This round robin involved four partners within NEMO. Each partner has measured three different samples: one 2D small depth grating, one 1D small depth grating and one 1D high aspect ratio grating. In order to get rid of the samples inhomogeneity, the measurements were performed exactly at the same location on each sample by all partners. This was achieved by using a multiscale resist pattern transferred on the gratings which precisely defined a 5×5 mum2 area. The paper will sum up the experimental values obtained by all the partners, draw general conclusions and make suggestions to improve the accuracy of AFM measurements.
Characterization of Micro-optics
Tunable Micro-optics, 2000
Nano- and Micro-Metrology
Connector device for coupling optical fibres, and method of production thereof
Tomographic study of polymer bridges between two optical fibers for telecommunication applications
Photonic Fiber and Crystal Devices: Advances in Materials and Innovations in Device Applications VII, 2013
ABSTRACT In this paper we present the tomographic studies of refractive index distribution in pol... more ABSTRACT In this paper we present the tomographic studies of refractive index distribution in polymer bridges between two optical fibers. Detailed refractive index maps are needed in order to improve the technological process of manufacturing of those bridges and to achieve lower return losses. At first the technological process of bridges fabrication through photopolymerization is presented. The interferometric measurements of reference fibers used to produce those bridges and two series of microbridges are performed in visible (632.8 nm) and infrared (1550 nm) experimental systems. The relations between vis and IR results are determined, which allows for performing tomographic measurements in more accurate conditions secured in visible spectrum. The experimentally obtained refractive index distributions in microbridges are used for modeling the insertion and return losses, which are compared with the real losses obtained for the produced microbridges. This knowledge will be used for better understanding of the manufacturing process and its further optimization.
Spectroscopy AS a “green” technique for food quality and safety applications
Technical Digest of the Eighteenth Microoptics Conference, 2013
ABSTRACT A selection of spectroscopy-based, fiber optic and micro-optic devices is presented. The... more ABSTRACT A selection of spectroscopy-based, fiber optic and micro-optic devices is presented. They have been designed and tested for monitoring the quality and safety of common foodstuffs. The absorption, fluorescence, reflection and Raman spectra, considered as product fingerprints, allowed to detecting quality indicators such as nutraceutic ingredients or indications of the production region, to authenticating products and detecting frauds, as well as spotting out harmful elements.
Microlens arrays fabricated by deep lithography with protons and their characterization
Proceedings of SPIE - The International Society for Optical Engineering
In this paper we present our latest results on the fabrication and characterization of plastic mi... more In this paper we present our latest results on the fabrication and characterization of plastic microlenslet arrays using Deep Lithography with Protons (DLP) and highlight their geometrical dimensions, their surface profile and their uniformity. We also present quantitative information on their optical characteristics such as focal length and spherical aberration as measured with a Mach-Zehnder interferometer. Furthermore we demonstrate the flexibility of the DLP technology to fabricate arrays of microlenses that feature different pitches and different sags. Although the DLP technology is a valuable tool to rapidly prototype refractive micro-optical components, the approach is unpractical for mass-fabrication. We therefore introduce a replication technique, called vacuum casting, which is very appropriate when only a few tens of copies have to be made, and we bring forward the first quantitative characteristics of these microlens replicas.
Two-dimensional plastic microlens arrays by deep lithography with protons: Fabrication and characterization
Journal of Optics A Pure and Applied Optics
We present a quantitative study of the fabrication process of two-dimensional plastic microlens a... more We present a quantitative study of the fabrication process of two-dimensional plastic microlens arrays fabricated using deep lithography with protons. Our process involves the proton irradiation of a PMMA (poly(methyl methacrylate)) sample in regions with a circular footprint followed by a diffusion of MMA vapour into the bombarded zones to cause a lens-shaped volume expansion. In the first part of
Proceedings of SPIE - The International Society for Optical Engineering
Novel interferometric measurement systems for the characterization of micro-optics
We report on Deep Lithography with Protons (DLP) as a promising, alternative technology for the f... more We report on Deep Lithography with Protons (DLP) as a promising, alternative technology for the fabrication of uniform, low-cost and replicable 1D cylindrical microlens arrays with high numerical apertures and chords ranging from 200µm to 1mm. After describing the different fabrication process steps, we will highlight the experimental characteristics of our cylindrical micro-lens arrays related to imaging and surface quality. Furthermore, we will illustrate the potentiality of DLP to offer suitable solutions for current problems in laser to fibre coupling by monolithically integrating these cylindrical micro-lens arrays with optical fibre-positioning U-grooves.
The efficient integration of arrays of opto-electronic devices into photonic data handling system... more The efficient integration of arrays of opto-electronic devices into photonic data handling systems calls for the development of high-quality, uniform microlensarrays. In this paper we present our latest results on the fabrication of plastic microlenslet arrays using Deep Lithography with Protons (DLP). We highlight the geometrical dimensions, the shape and the uniformity of our microlensarrays measured in reflection mode with an optical non-contact profiler. Next we present the optical performances of the microlenses. A Mach-Zehnder interferometer was used here to measure the focal length, the aberrations and the deviation from sphericity of the microlenses. Aberrations/lambda RMS 0.209 P -V 1.057 Distance of lines 0.1 RMS 0.22 P -V 1.09 Deviation from spherical wavefront/lambda Phaseshift/lambda Phaseshift/lambda
Simulation, fabrication and characterization of microlens oriented fluorescence detection systems for DNA microarrays
Page 1. Fig. 1. Illustration of flexible, conformal transducer array design. Simulation, Fabricat... more Page 1. Fig. 1. Illustration of flexible, conformal transducer array design. Simulation, Fabrication, and Characterization of a Novel Flexible, Conformal Ultrasound Transducer Array Rahul S. Singh, Member, IEEE,1,2 Martin O. Culjat ...
Refractive and diffractive mico-optics in optical interconnects
Proceedings of SPIE - The International Society for Optical Engineering
Uploads
Papers by Heidi Ottevaere