Nonlinear laser cavities as nonclassical light sources

Light-emitting atoms or material in a cavity are well known to generate thermal or coherent fields depending on, e.g., the quality of the cavity and the strength of the excitation of the emitting material. We investigate the possibilities of generating antibunched photons and nonclassical light by adding nonlinear elements in the cavity and show that it is indeed feasible. In particular, we focus on cavities with emitters formed by macroscopic many-body systems like gas of excitons in semiconductor quantum wells where different nonlinearities in the emitters and absorbers will be shown to lead to bunched, Poissonian, and antibunched photon statistics. We show that, while the single two-state system with suitable coupling parameters can produce antibunched photons, macroscopic systems need an additional nonlinearity to generate antibunching phenomenon. Our results demonstrate that a nonclassical cavity field can be generated by a conventional laser when a suitable nonlinear absorbing element is added to the cavity structure. Thus, the proposed device configuration can be manufactured using standard optoelectronic materials and processing techniques