Quantum analysis of optical parametric fluorescence in the optical parametric amplification process

Abstract

The temporal contrast of the ultra-intense laser pulse can be degraded by optical parametric fluorescence (OPF) in high-gain and pulse-pumped optical parametric amplification (OPA). However, to the best of our knowledge, no theory is proposed to describe the quantum noise in such conditions from the first principle. In this paper, we propose a theory based on the quantization of energy flux and a linearization method for investigating both lasers and the OPF in high-gain and pulse-pumped OPA. Following the proposal, the amplification of laser is consistent with classical nonlinear optics. Moreover, an analytical formula of OPF energy is obtained under undepleted and quasi-monochromatic pump conditions. A simplified formula is also obtained under the assumption of small spectral width and acceptant solid angle. Furthermore, a formula of the OPF duration is obtained with a Gaussian pump pulse. Excellent consistency is achieved between previous experiments and our theory.