Phenomenological theory of generation of squeezed light states by a superradiant laser

S. Kielich, R. Tanaś, Roman Zawodny

A phenomenological (classical) and quantum treatment of the laser light-intensity-induced Faraday effect in isotropic media and crystals is given. The effect, being universal (occurring in all matter), is shown to act as a stimulator controlling the self-squeezing of light: depending on the helicity of circular polarization of the light wave and on the sense of the dc magnetic field, the sign of the pseudoscalar parameter of nonlinear coupling changes leading to an enhancement or weakening of self-squeezing. Moreover, by varying the state of polarization of the light wave or the magnetic field strength, control of the efficiency of light-squeezing generation can be achieved.

M. D. Reid, Alistair S. Lane, Daniel F. Walls

Da-Wu Xiao, Chong Chen, Ren-Bao Liu

In conventional lasers, the emitters are typically incoherent, radiating photons independently; in superradiant lasers, many coherent emitters radiate photons collectively, but they essentially do not interact with each other. Here, we present the concept of quantum many-body lasers, in which the emitters interact coherently and radiate collectively. In this proof-of-concept study, we consider a cavity coupled to many pumped spin-1/2 emitters with all-to-all interaction. We find that the squeezing induced by the coherent many-body interaction can be transferred from the spins to photons through superradiant lasing. This work illustrates the concept of using a pumped quantum many-body system to generate bright quantum light with quantum correlations beyond conventional optical coherence, which can facilitate quantum technologies and the study of nonlinear optics in the quantum realm.

Sergey V. Prants

Harry J. Kimble

В. Н. Горбачев, Andrew I. Trubilko

We propose a theory that makes it possible to examine both laser and micromaser two-photon light generation. The theory is based on the Lamb-Scully model, in which two-level atoms have initial coherence. Such an initial state allows for light generation involving atoms without inversion or even atoms with negative population inversion in the transition. We analyze the conditions needed for the emergence of squeezed states of the light field. We also show that the photon statistics in lasing is always classical but that there appears a state of the field squeezed in the phase with maximum photodetection shot-noise suppression. For a micromaser we find a regime where sub-Poisson light with a shot-noise suppression level of 60% is realized in an inversionless transition. In another regime, a squeezed state that produces 75% suppression of noise can be generated.