Phase noise quenching in a four-level laser via squeezed vacuum - Javaid Anwar

It is shown by Gea-Banacloche "Phys. Rev Lett. 59, 543 (1987)" that the Laser Phase diffusion rate may be reduced by as much as one-half when laser is coupled out through a partially transmitting mirror to ¡°squeezed vacuum¡± as opposed to ordinary vacuum. This happens for a particular choice of the phase of the squeezed field. However, phase stability is not achieved for this choice of phase. In this paper, this analysis is extended by including a separate squeezed vacuum reservoir which couples the spontaneous decay between the lasing levels. The results show that, it is possible to obtain the phase stability as well as phase noise quenching in this system.