E. M. L. English

Publications (4)0 Total impact

• Conference Proceeding: Flywheel oscillator for atomic fountain clocks using ultra-stable lasers and a fiber-based optical frequency comb

  J. Millo, Y. Le Coq, S. Bize, J. Guena, H. Jiang, M. Abgrall, E.M.L. English, A. Clairon, G. Santarelli, M.E. Tobar
  [show abstract] [hide abstract]
  ABSTRACT: We demonstrate the use of a fiber-based femtosecond laser locked onto an ultrastable optical cavity to generate a low-noise microwave reference signal. Comparison with both a cryogenic sapphire oscillator (CSO) and a titanium-sapphire-based optical frequency comb system exhibit a stability of about 3 times 10^-15 between 1 and 10 s. The microwave signal from the fiber system is used to perform Ramsey spectroscopy in a state-of-the-art cesium fountain clock. The resulting clock is compared to the CSO and exhibits a stability of 3.5 times 10^-14 tau^-frac12.
  Frequency Control Symposium, 2009 Joint with the 22nd European Frequency and Time forum. IEEE International; 05/2009
• Source

  Available from: ArXiv

  Article: Ultrastable lasers based on vibration insensitive cavities

  J. Millo, D. V. Magalhaes, C. Mandache, Y. Le Coq, E. M. L. English, P. G. Westergaard, J. Lodewyck, S. Bize, P. Lemonde, G. Santarelli
  [show abstract] [hide abstract]
  ABSTRACT: We present two ultra-stable lasers based on two vibration insensitive cavity designs, one with vertical optical axis geometry, the other horizontal. Ultra-stable cavities are constructed with fused silica mirror substrates, shown to decrease the thermal noise limit, in order to improve the frequency stability over previous designs. Vibration sensitivity components measured are equal to or better than 1.5e-11 per m.s^-2 for each spatial direction, which shows significant improvement over previous studies. We have tested the very low dependence on the position of the cavity support points, in order to establish that our designs eliminate the need for fine tuning to achieve extremely low vibration sensitivity. Relative frequency measurements show that at least one of the stabilized lasers has a stability better than 5.6e-16 at 1 second, which is the best result obtained for this length of cavity. Comment: 8 pages 12 figures
  01/2009;
• Source

  Available from: Michael E. Tobar

  Article: Ultra-low noise microwave generation with fiber-based optical frequency comb and application to atomic fountain clock

  J. Millo, M. Abgrall, M. Lours, E. M. L. English, H Jiang, J. Guena, A. Clairon, S. Bize, Y. Le Coq, G. Santarelli, M.E. Tobar
  [show abstract] [hide abstract]
  ABSTRACT: We demonstrate the use of a fiber-based femtosecond laser locked onto an ultra-stable optical cavity to generate a low-noise microwave reference signal. Comparison with both a liquid Helium cryogenic sapphire oscillator (CSO) and a Ti:Sapphire-based optical frequency comb system exhibit a stability about $3\times10^{-15}$ between 1 s and 10 s. The microwave signal from the fiber system is used to perform Ramsey spectroscopy in a state-of-the-art Cesium fountain clock. The resulting clock system is compared to the CSO and exhibits a stability of $3.5\times10^{-14}\tau^{-1/2}$. Our continuously operated fiber-based system therefore demonstrates its potential to replace the CSO for atomic clocks with high stability in both the optical and microwave domain, most particularly for operational primary frequency standards. Comment: 3 pages, 3 figures
  01/2009;
• Article: Ultralow noise microwave generation with fiber-based optical frequency comb and application to atomic fountain clock

  J Millo, M Abgrall, M Lours, E M L English, H Jiang, J Guena, A Clairon, M E Tobar, S Bize, Y Le Coq, G Santarelli
  [show abstract] [hide abstract]
  ABSTRACT: We demonstrate the use of a fiber-based femtosecond laser locked onto an ultrastable optical cavity to generate a low-noise microwave reference signal. Comparison with both a cryogenic sapphire oscillator (CSO) and a titanium-sapphire-based optical frequency comb system exhibit a stability of about 3x10(-15) between 1 and 10 s. The microwave signal from the fiber system is used to perform Ramsey spectroscopy in a state-of-the-art cesium fountain clock. The resulting clock is compared to the CSO and exhibits a stability of 3.5x10(-14)tau(-1/2)
  Appl. Phys. Lett. 94(14):141105.