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 〈(Δφ${)}^2$〉 versus time, we obtain the expected behavior: namely, for Dt∼1 the Schawlow-Townes linewidth and for t≫${\mathit{D}}^{\mathrm{-}1}$ 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.

• Received 20 July 1990

DOI:https://doi.org/10.1103/PhysRevA.43.554