Quantum beat laser as a source of entangled radiation

Abstract

We consider a quantum beat laser ͓Scully and Zubairy, Phys. Rev. A 35 752 ͑1987͔͒ as a source of entangled radiation. The system essentially consists of three-level atoms inside a doubly resonant cavity such that coherence is introduced by driving the upper two levels with a strong classical field of Rabi frequency ⍀. We study the dynamics of this system for different values of Rabi frequencies in the presence of cavity losses. It is shown that entanglement can be generated in this system for different initial states of the field in the two modes.

Effect of phase fluctuation and dephasing on the dynamics of entanglement generation in a correlated emission laser

“…Addressing the contribution of every phase change does not seem practically realistic. Consequently, assuming the phase fluctuations as a Gaussian random process [10,11,15] and using the deviation of the phase fluctuation instead of the actual phase led to more tractable situation [9]. With similar conviction, employing the property of the Gaussian variables [24], one can express…”

“…These studies are usually confined to the steady state case [1,31] or numerical solution for selected parameters [3,15]. However, in this article, upon using the rate of dephasing and deviation of the phase fluctuation as a probe, the evolution of the entanglement is studied when Ω = 0.…”

“…In the study of the time evolution of a similar system when many parameters are involved, the usual approach is numerically calculating the required correlations making use of either the characteristic function [3,7] or the rate equation [10,15]. However, in this article, the dynamics of the cavity radiation is analyzed following a straightforward analytic procedure recently outlined elsewhere [1,8,9,13].…”

“…The atoms prepared in this manner are injected into the cavity at a constant rate and externally driven with a resonant coherent radiation while traversing the cavity. It is not difficult to envision that the pumping radiation could have also led to phase fluctuations; whose effect was thoroughly addressed elsewhere [7,15,17]. Moreover, taking the recent advance in locking a phase in such a system into consideration, the rate at which the coherence superposition decays is set to be less than the spontaneous atomic decay rate.…”

“…In these studies the phase and photon number operators are presumed to fulfill a canonical commutation relation. In a more recent times, assuming the phase as randomly fluctuating c-number parameter, it is shown that the phase fluctuations substantially decrease the degree of entanglement [7,15]. Investigation of a similar nature where the coherence is assumed to be partially prepared is also considered [8][9][10].…”