Quantum correlations and fluctuations in the pulsed light produced by a synchronously pumped optical parametric oscillator below its oscillation threshold
V. A. Fock Physics Institute, St. Petersburg State University, Stary Petershof, ul. Ul'yanovskaya, 1, 198504 St. Petersburg, Russia
2 Laboratoire Kastler Brossel, Université Pierre et Marie Curie-Paris 6, Place Jussieu, CC74, 75252 Paris Cedex 05, France
Corresponding author: a Yuri.Golubev@gmail.com
Revised: 13 September 2010
Published online: 5 November 2010
We present a simple quantum theory for the pulsed light generated by a synchronously pumped optical parametric oscillator (SPOPO) in the degenerate case where the signal and idler trains of pulses coincide, below threshold and neglecting all dispersion effects. Our main goal is to precise in the obtained quantum effects, which ones are identical to the c.w. case and which ones are specific to the SPOPO. We demonstrate in particular that the temporal correlations have interesting peculiarities: the quantum fluctuations at different times within the same pulse turn out to be totally not correlated, whereas they are correlated between nearby pulses at times that are placed in the same position relative to the center of the pulses. The number of significantly correlated pulses is of the order of cavity finesse. We show also that there is perfect squeezing at noise frequencies = 2π m/TR (m = 0, 1, 2, where TR is the pulse train period) when one approaches the threshold from below on the signal field quadrature measured by a balanced homodyne detection with a local oscillator of very short duration compared to the SPOPO pulse length.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2010