Phase fluctuations in a laser with atomic memory effects.

Abstract

We calculate phase fluctuations of the phase operator defined by Pegg and Barnett [Europhys. Lett. 6, 483 (1988); J. Mod. Opt. 36, 7 (1989); Phys. Rev. A 39, 1665 (1989)] in a laser with atomic memory effects. First, we compute the phase fluctuations of a laser, using the Scully-Lamb theory. In a single curve of 〈(\ensuremath{\Delta}\ensuremath{\varphi}${)}^{2}$〉 versus time, we obtain the expected behavior: namely, for Dt\ensuremath{\sim}1 the Schawlow-Townes linewidth and for t\ensuremath{\gg}${\mathit{D}}^{\mathrm{\ensuremath{-}}1}$ the phase fluctuations corresponding to a random phase. As we include the atomic memory effects, we obtain a noise reduction for times of the order of the atomic decay time.