Patrick Juncar

Publications (10)8.41 Total impact

• Article: Theoretical analysis for the design of the French watt balance experiment force comparator.

  Patrick Pinot, Gerard Genevès, Darine Haddad, Jean David, Patrick Juncar, Michel Lecollinet, Stéphane Macé, François Villar
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  ABSTRACT: This paper presents a preliminary analysis for designing a force comparator to be used in the French watt balance experiment. The first stage of this experiment consists in a static equilibrium, by means of a mechanical beam balance, between a gravitational force (a weight of an artefact having a known mass submitted to the acceleration due to the gravity) and a vertical electromagnetic force acting on a coil driven by a current subject to the magnetic induction field provided by a permanent magnet. The principle of the force comparison in the French experiment is explained. The general design configuration of the force balance using flexure strips as pivots is discussed and theoretical calculation results based on realistic assumptions of the static and dynamic behaviors of the balance are presented.
  Review of Scientific Instruments 10/2007; 78(9):095108. · 1.37 Impact Factor
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  Available from: uvsq.fr

  Article: Highly accurate positioning control method for piezoelectric actuators based on phase-shifting optoelectronics

  Luc Chassagne, Suat Topcu, Yasser Alayli, Patrick Juncar
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  ABSTRACT: We propose a sub-nanometric positioning control method for piezoelectric actuators based on a home-made high frequency phase shifting electronic circuit and a heterodyne interferometer. The method has been set up. Using a readily available piezoelectric actuator, we demonstrate that our method allows back and forth displacement without nonlinearities. Repeatability of 0.053 nm has been obtained over 1 µm displacement range. Displacement steps as low as 260 pm are presented. Such a method could be very useful for the nanotechnology and nanometrology communities for nano-scale manipulations or nano-assembly applications.
  Measurement Science and Technology 07/2005; 16(9):1771. · 1.49 Impact Factor
• Article: High accuracy velocity control method for the french moving-coil watt balance

  Suat Topcu, Luc Chassagne, Darine Haddad, Yasser Alayli, Patrick Juncar
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  ABSTRACT: We describe a novel method of velocity control dedicated to the French moving-coil watt balance. In this project, a coil has to move in a magnetic field at a velocity of 2 mm s ^-1 with a relative uncertainty of 10^-9 over 60 mm. Our method is based on the use of both a heterodyne Michelson’s interferometer, a two-level translation stage, and a homemade high frequency phase-shifting electronic circuit. To quantify the stability of the velocity, the output of the interferometer is sent into a frequency counter and the Doppler frequency shift is recorded. The Allan standard deviation has been used to calculate the stability and a σ_y(τ) of about 2.2×10^-9 over 400 s has been obtained.
  Review of Scientific Instruments 12/2004; · 1.37 Impact Factor
• Article: Temp Symposium Entry

  Mark D. Plimmer, Thomas Badr, Stephane Guerandel, Yann Louyer, Sylvestre Challemel du Rozier, Patrick Juncar, Marc E. Himbert, Joshua D. Silver, Francois Biraben, Francois Nez, Gaetan Hagel
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  ABSTRACT: We report advances towards the development of frequency standards based on narrow two-photon transitions in the silver atom at 576 and 661 nm from the ground 4d105s2S1/2 state to the 2D3/2,5/2 levels of the configuration 4d95s2. We describe detection schemes for metastable atoms, localisation of the position of the metastable 2D5/2 level and diode-pumped Nd:YLF lasers around 1.3 μm destined to replace dye lasers for both cooling and spectroscopy of the clock transition. Our result for the position of the 2D5/2 level is more than a factor of two improvement over previous vales.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
  06/2004;
• Article: Doubled single-frequency Nd:YLF ring laser coupled to a passive nonresonant cavity.

  Yann Louyer, Patrick Juncar, Mark D Plimmer, Thomas Badr, François Balembois, Patrick Georges, Marc E Himbert
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  ABSTRACT: We demonstrate an original solution to obtain a single-frequency ring laser coupled to an external passive nonresonant ring cavity, which plays the role of an optical diode. This system provides more output power than systems with an intracavity unidirectional device. To the best of our knowledge, this work marks the first demonstration of a unidirectional planar ring laser at 1.3 microm. Using 12 W at 797 nm to pump a Nd:YLF laser, combined with intracavity second-harmonic generation, we achieve yields of 440 mW at 661.3 nm and 340 mW at 656.0 nm.
  Applied Optics 04/2004; 43(8):1773-6. · 1.41 Impact Factor
• Article: Heterodyne interferometric technique for displacement control at the nanometric scale

  Suat Topcu, Luc Chassagne, Darine Haddad, Yasser Alayli, Patrick Juncar
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  ABSTRACT: We propose a method of displacement control that addresses the measurement requirements of the nanotechnology community and provide a traceability to the definition of the mèter at the nanometric scale. The method is based on the use of both a heterodyne Michelson’s interferometer and a homemade high frequency electronic circuit. The system so established allows us to control the displacement of a translation stage with a known step of 4.945 nm. Intrinsic relative uncertainty on the step value is 1.6×10−9. Controls of the period of repetition of these steps with a high-stability quartz oscillator permits to impose an uniform speed to the translation stage with the same accuracy. This property will be used for the watt balance project of the Bureau National de Métrologie of France. © 2003 American Institute of Physics.
  Review of Scientific Instruments 10/2003; 74(11):4876-4880. · 1.37 Impact Factor
• Article: Nd:YLF laser at 1.3 microm for calcium atom optical clocks and precision spectroscopy of hydrogenic systems.

  Yann Louyer, Mark D Plimmer, Patrick Juncar, Marc E Himbert, François Balembois, Patrick Georges
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  ABSTRACT: We describe single-frequency operation of a diode-pumped Nd:YLF laser in the range 1311.9-1317.2 nm. It can be used for the interrogation of the clock transition in calcium (1314.0 nm) or spectroscopy in hydrogen and metastable singly ionized helium (1312.6 nm). By using a twisted-mode cavity, we have obtained output powers of 830 and 970 mW at 1312.6 and 1314.0 nm, respectively, in a single longitudinal mode.
  Applied Optics 09/2003; 42(24):4867-70. · 1.41 Impact Factor
• Article: Nd:YLF laser at 1.3 mum for calcium atom optical clocks and precision spectroscopy of hydrogenic systems

  Yann Louyer, Mark D. Plimmer, Patrick Juncar, Marc E. Himbert, François Balembois, Patrick Georges
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  ABSTRACT: We describe single-frequency operation of a diode-pumped Nd:YLF laser in the range 1311.9-1317.2 nm. It can be used for the interrogation of the clock transition in calcium (1314.0 nm) or spectroscopy in hydrogen and metastable singly ionized helium (1312.6 nm). By using a twisted-mode cavity, we have obtained output powers of 830 and 970 mW at 1312.6 and 1314.0 nm, respectively, in a single longitudinal mode.
  Applied Optics - APPL OPT. 01/2003; 42(24):4867-4870.
• Article: Contrôle de position et de vitesse à l'échelle nanométrique dans la balance du watt du LNE Position and velocity control at the nanometric scale in the LNE watt balance

  Darine HADDAD, Luc CHASSAGNE, Patrick JUNCAR, Suat TOPÇU
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  ABSTRACT: Abstract
• Article: Absolute position sensor using Gaussian beam propagation properties and their spatial modulation

  Darine Haddad, Patrick Juncar, Gérard Genevès, Patrick Pinot
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  ABSTRACT: Authors propose a new approach in displacement measurements based on Gaussian beam propagation, their focusing properties and their spatial modulation. Two modulated Gaussian beams with a phase shift of 180° are focused on a slit fixed to the moveable object. The resulting laser beams at the slit output are focused into a multimode fiber. A lock-in amplifier demodulates the photodiode signal placed at the multimode fiber output. The lock in-amplifier output signal is a function of the slit displacement. The sensor is completely fibered with no electrical wires so it presents no heat dissipation near the moveable object and is compatible with vacuum use. It is a contactless sensor and provides a simple compact design and cost-effective means of achieving high resolution absolute displacement measurements. The preliminary experimental data of the sensor calibration by laser interferometry have shown a resolution of 0.1 nm.
• Article: Polarimetric Michelson interferometer for sub-nanometric scale positionning control

  Suan Xu, Luc Chassagne, Suat Topcu, Yasser Alayli, Patrick Juncar
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  ABSTRACT: Step by step displacements control scheme based on polarimetric interferometer is proposed. A repeatability of 470 pm is obtained on back and forth displacements over micrometer range using piezoelectric actuators. The error induced on the position due to a residual ellipticity of the laser beam is investigated. Such method could be extended over millimeter range displacements leading to numerous applications in nanometrology.