Laurent Couraud

Laboratoire de Photonique et de Nanostructures, Marcoussis, Île-de-France, France

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Publications (4)2.5 Total impact

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    ABSTRACT: A n-InP/n-Si isotype heterojunction is fabricated using direct oxide-free bonding, to study electrical transport in this hybrid material system. The band alignment is first evaluated numerically and a theoretical I(V) curve is discussed. The diode is then fabricated and the experimental I(V) curve is compared against theory.
    2014 26th International Conference on Indium Phosphide and Related Materials (IPRM); 05/2014
  • H. Salmon, L. Couraud, Gilgueng Hwang
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    ABSTRACT: The development of new mobile microrobotic swimmers, limited by low Reynolds dynamics and stiction effects in confined environments, should aim for efficient propulsion mechanisms in wet confined environments and more elaborated manipulation strategies. We first introduced a novel type of microrobots called MagPol (Magnetic Polarizable) integrated in a microfluidic chip controlled through magnetic waves. We developed a simple method analyzing rotational dynamics to characterize swimming performances inside microfluidic environments and provide experimental criteria to improve hydrodynamics of future designs. Magpols demonstrated their in-plane mobilities, with a maximum speed up-to 566 millimeters per second (1390 body lengths per second), and the completions of sophisticated trajectory through the microchannels, forward or backward. In addition to their enhanced planar mobilities, we newly demonstrated a backward towing technique by reversing intrinsic magnetic moment.
    Robotics and Automation (ICRA), 2013 IEEE International Conference on; 01/2013
  • H. Salmon, L. Couraud, G. Hwang
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    ABSTRACT: Sensing magnetization and enhancing dynamics performances is essential while studying wireless magnetic mobile robots. Sensing physical parameters in microfluidic environments has strongly been demanded in various lab-on-a-chip applications as well. In this paper, we propose mobile microrobots as mobile sensor in microfluidics. We develop an original environment for highresolution dynamic tracking and analysis in microfluidic chips. Studying robot dynamics in low Reynolds fluid with no magnetic sensor in the chip is challenging as the field distribution and robot magnetization are not well known. Our intended goal is to explore intrinsic magneto-fluidic sensing capacities to collect more information on the microsystem. We successfully integrate our robot into a transparent microfluidic chip for high-temporal resolution analysis of dynamics. We develop an electromagnetic setup allowing complete remote control (at low power) of rotational behaviour. We study a breakdown phenomenon up to 1kHz signal and develop a scalar method analyzing rotational dynamics to enhance their sensing capacity.
    Intelligent Robots and Systems (IROS), 2013 IEEE/RSJ International Conference on; 01/2013
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    ABSTRACT: Micro and nanoscale mobile agents capable of self-propulsion in low Reynolds number fluids would have a great technological impact in many fields. Few known mechanisms are able to propel such devices. Here we describe helical nanobelt (HNB) swimmers actuated by an electric field-generated electro-osmotic force. These HNB swimmers are designed with a head and a tail, similar to natural micro-organisms such as bacteria and their flagella. We show that these electro-osmotic propulsion of HNB swimmers achieve speeds (24 body lengths per second), force (1.3 nN), and pressure (375.5 Pa) above those demonstrated by other artificial swimmers based on physical energy conversion. Although nature’s bacteria are still more dynamic, this paper reports that the demonstrated electro-osmotic HNB microswimmers made a big step toward getting closer to their performances. Moreover, an unusual swimming behavior with discontinuous pumping propulsion, similar to jellyfish, was revealed at or above the speculated marginal limit of linear propulsion. These electro-osmosis propelled HNB swimmers might be used as biomedical carriers, wireless manipulators, and as local probes for rheological measurements.
    The International Journal of Robotics Research 06/2011; 30:806-819. DOI:10.1177/0278364911407231 · 2.50 Impact Factor