34documents trouvés
Self-mixing laser sensor for large displacements: signal recovery in the presence of speckle
U.ZABIT, O.BERNAL, T.BOSCH
OSE
Revue Scientifique : IEEE Sensors Journal, Vol.13, N°2, pp.824-831, Février 2013 , N° 12667
Lien : http://hal.archives-ouvertes.fr/hal-00762287
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Abstract
Laser self-mixing (SM) sensors have been successfully used to measure displacement in the absence of speckle. However, speckle deforms the SM signal rendering it unusable for standard displacement extraction techniques. This article proposes a new signal processing technique, based on tracking the signal envelope, to remedy this problem. Algorithm was successfully employed to measure long-range displacements (25 mm), in the presence of speckle and the lateral movement of the target, both causing severe corruption of the SM signal. It therefore enabled the use of the sensor on non-cooperative targets without the need for sensor positioning and/or alignment. The results have been obtained for SM signals where the envelope amplitude has varied by a factor 28, without a loss of interferometric fringes. The use of this technique effectively removes the need for opto/electro-mechanical components traditionally used to measure long-range displacement in the presence of speckle.
Flow profile measurement in microchannel using the optical feedback interferometry sensing technique
L.CAMPAGNOLO, M.NIKOLIC, J.PERCHOUX, Y.L.LIM, K.BERTLING, K.LOUBIERE, L.PRAT, A.D.RAKIC, T.BOSCH
OSE, Queensland, LGC
Revue Scientifique : Microfluidics and Nanofluidics, Vol.14, N°1-2, pp.113-119, Janvier 2013 , N° 13003
Lien : http://hal.archives-ouvertes.fr/hal-00757538
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Abstract
The need to accurately measure flow profiles in microfluidic channels is well recognised. In this work, we present a new optical feedback interferometry (OFI) flow sensor that accurately measures local velocity in fluids and enables reconstruction of a velocity profile inside a microchannel. OFI is a self-aligned interferometric technique that uses the laser as both the transmitter and the receiver thus offering high sensitivity, fast response, and a simple and compact optical design. The system described here is based on a commercial semiconductor laser and has been designed to achieve a micrometer-range spatial resolution. The sensor performance was validated by reconstructing the velocity profile inside a circular cross-section flow-channel with 320 µm internal diameter, with a relative error smaller than 1.8 %. The local flow velocity is directly measured, thus avoiding the need for model based profile calculation and uncertainties inherent to this approach. The system was validated by successfully extracting the flow profiles in both Newtonian and shear-thinning liquids.
A new optical feedback interferometer for measuring red blood cell velocity distributions in individual capillaries: a feasibility study in microchannels
L.CAMPAGNOLO, S.ROMAN, J.PERCHOUX, S.LORTHOIS
OSE, TEAM, IMFT
Manifestation avec acte : Congrès Annuel de la Société de Bioméchanique 2012 du 16 octobre au 19 octobre 2012, Toulouse (France), Prix du meilleur poster, 2012, 2p. , N° 12347
Lien : http://hal.archives-ouvertes.fr/hal-00714045
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Abstract
The dynamics of blood flow in microvascular networks is of great importance in the exchange of nutrient and waste substances between blood and living tissues. In these vessels of diameter less than 100µm, the development of quantitative methods for measuring the velocity of red blood cells (RBCs) is still challenging. In this context, the Dual-Slit (DS) technique, a temporal correlation technique, is commonly used. Our group has recently shown that, provided that several operational conditions are fulfilled, this technique can provide a precise measurement of the transverse velocity profile of RBCs. The measured velocities are maximal velocities in the depth of the channel . However, this technique requires expensive equipment (high speed camera) and the related data-treatment is time consuming. Moreover, the duration of the acquisition is long (typically 2 to 40s). For these reasons, on line measurements, especially in cases of transient regimes, are not possible. The aim of the present work is to determine whether Optical Feedback Interferometry, a new optical technique in the microfluidic domain which is based on the optical feedback effect in laser diodes, can be used to perform quantitative measurements of RBCs velocity in channels of size less than 100µm. Optical Feedback Interferometers (OFI) are indeed compact, low cost and simple sensors. They are known for providing much shorter response times than DS, currently lower than 10ms, while keeping the precision of traditional Laser Doppler Interferometers. This technique has been previously applied and validated to measure velocity profiles in 300µm diameter channels, but its feasibility in smaller channels is still to be demonstrated. For that purpose, the velocity profiles obtained by OFI and DS are compared, using PDMS microchannels and spheric monodisperse particle suspensions in set-up configurations where the DS has been previously validated.
Graphene in silicon photovoltaic cells
H.TAP, B.CAUSSAT, H.VERGNES, P.TRINSOUTROT, V.CONEDERA, F.GUERIN, F.GESSINN, J.GRISOLIA, J.LAUNAY, P.ARGUEL
OSE, LGC, TEAM, AIME, LPCNO, MICA, PH
Manifestation avec acte : International Conference on Micro and Nano Engineering (MNE 2012), Toulouse (France), 16-20 Septembre 2012, 3p. , N° 12299
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128205A new optical feedback interferometer for measuring red blood cell velocity distributions in individual capillaries: a feasibility study in microchannels
L.CAMPAGNOLO, S.ROMAN, J.PERCHOUX, S.LORTHOIS
OSE, TEAM, IMFT
Revue Scientifique : Computer Methods in Biomechanics and Biomedical Engineering, Supplément 1, Vol.15, pp.104-105, Septembre 2012 , N° 12347
Lien : http://hal.archives-ouvertes.fr/hal-00714045
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Abstract
The dynamics of blood flow in microvascular networks is of great importance in the exchange of nutrient and waste substances between blood and living tissues. In these vessels of diameter less than 100µm, the development of quantitative methods for measuring the velocity of red blood cells (RBCs) is still challenging. In this context, the Dual-Slit (DS) technique, a temporal correlation technique, is commonly used. Our group has recently shown that, provided that several operational conditions are fulfilled, this technique can provide a precise measurement of the transverse velocity profile of RBCs. The measured velocities are maximal velocities in the depth of the channel . However, this technique requires expensive equipment (high speed camera) and the related data-treatment is time consuming. Moreover, the duration of the acquisition is long (typically 2 to 40s). For these reasons, on line measurements, especially in cases of transient regimes, are not possible. The aim of the present work is to determine whether Optical Feedback Interferometry, a new optical technique in the microfluidic domain which is based on the optical feedback effect in laser diodes, can be used to perform quantitative measurements of RBCs velocity in channels of size less than 100µm. Optical Feedback Interferometers (OFI) are indeed compact, low cost and simple sensors. They are known for providing much shorter response times than DS, currently lower than 10ms, while keeping the precision of traditional Laser Doppler Interferometers. This technique has been previously applied and validated to measure velocity profiles in 300µm diameter channels, but its feasibility in smaller channels is still to be demonstrated. For that purpose, the velocity profiles obtained by OFI and DS are compared, using PDMS microchannels and spheric monodisperse particle suspensions in set-up configurations where the DS has been previously validated.
Laser dynamics in sawtooth-like self-mixing signals
R.TEYSSEYRE, F.BONY, J.PERCHOUX, T.BOSCH
OSE
Revue Scientifique : Optics Letters, Vol.37, N°18, pp.3771-3773, Septembre 2012 , N° 12738
Lien : http://hal.archives-ouvertes.fr/hal-00757566
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Abstract
In this Letter, we experimentally show that transient phenomenons in self-mixing signals from a moving target contain information about the target reflectivity and distance. These transient phenomenons are well explained with a dynamical model of the laser diode, which is used to trace an abacus giving the target reflectivity and distance from a measured high-bandwidth, self-mixing signal.
Qualifying a CMOS instrumentation chain for charged particles detection in the space environment
F.BOUYJOU, O.BERNAL, H.TAP, G.PICAUT, J.A.SAUVAUD
OSE, EXT, IRAP
Manifestation avec acte : International Workshop on Analogue and Mixed Signal Integrated Circuits For Space Applications (AMICSA 2012), Noordwijk (Pays Bas), 27-29 Août 2012, 7p. , N° 12542
Lien : http://hal.archives-ouvertes.fr/hal-00737979
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Abstract
For the solar system exploration and the distant universe study, the in-situ particle energy measurement and/or the electron/ion event detection are needed. For our on-board satellite application, the particle sensor that is used to convert particle momentum into measurable electrical charges is a Microchannel plate (MCP). The performances of such a sensor depend on the Analog-Front-End (AFE) circuit used to process the incoming charges. Consequently, a CMOS instrumentation chain for charged particle detection has been designed and tested under space environment. This AFE contains 16 channels, all of which includes a charge pre-amplifier (CPA), a pulse shaper (PS) and a monostable circuit to perform the detection. Using a standard 0.35 μm CMOS process, the proposed AFE has a conversion gain of 0.9mV/fC for electrons and a power consumption of 2.15 mW per channel. Its dynamic range is 79 dB and it is possible to convert charges up to 1.5 pC. The circuit works properly from -20 to 80°C with a measured analog gain variation of 1μV.fC-1.K-1. As far as crosstalk is concerned, experiments show that the proposed instrumentation chain can detect negative charges down to 122 fC without any ambiguity. Further, the proposed chain was irradiated at an average rate of 140 rads (Si) per hour up to 360 krad without any functionality loss.
Dual-modulation fiber Fabry-Perot interferometer with double reflection for slowly-varying displacements
HC.SEAT, P.CHAWAH, M.CATTOEN, A.SOURICE, G.PLANTIER, F.BOUDIN, J.CHERY, C.BRUNET, P.BERNARD, M.SULEIMAN
OSE, Geoscience, CNRS, ESEO, IPGP, LNCMI-T
Revue Scientifique : Optics Letters, Vol.37, N°14, pp.2886-2888, Juillet 2012 , N° 12774
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129068Digital to analog conversion methodology applied to self-mixing displacement signals
A.LUNA ARRIAGA, F.BONY, T.BOSCH
OSE
Manifestation avec acte : International Conference on Vibration Measurements by Laser and Noncontact Techniques (AIVELA 2012), Ancona (Italie), 27-29 Juin 2012, pp.125-131 , N° 12485
Lien : http://hal.archives-ouvertes.fr/hal-00716538
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128046Error analysis due to laser beams misalignment of a double laser self-mixing velocimeter
B.TANIOS, F.BONY, T.BOSCH
OSE
Manifestation avec acte : International Conference on Vibration Measurements by Laser and Noncontact Techniques (AIVELA 2012), Ancona (Italie), 27-29 Juin 2012, pp.139-147 , N° 12436
Lien : http://hal.archives-ouvertes.fr/hal-00717214
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