Nonlinear version of Einstein coefficients in parametric conversions
Shin Arahira, Hitoshi Murai, Hironori Sasaki · Journal of the Optical Society of America B · 2017
In this paper, we report an experimental investigation on the relation between efficiencies of stimulated and spontaneous parametric conversion processes in nonlinear optical devices. We have found that the generation rate of photon pairs in the spontaneous process, μ, and the conversion efficiency in the stimulated process, η, had a simple linear relationship of μ=Kη. The factor of proportionality, K, was found to be 1 pair/Hz/s, regardless of the types of the devices and the parametric processes. This new finding implies that there is a simple relationship, like the Einstein coefficients, between the spontaneous and the stimulated processes of optical nonlinearities.