Analysis of the operation of eye-safe radiation sources based on OPOs taking into account pump depletion

We propose a method for calculating parameters of the eye safe parametric converter, considering the largest number of factors existing under real conditions and a limit of the conversion efficiency. We present the results of a theoretical study of single-cavity parametric generation in depleted pump approximation, where it is possible to simultaneously consider the influence of the intensity of the idler wave, the phase mismatch between interacting waves, losses on mirrors during reflection, as well as absorption in a nonlinear medium. When analyzing in the constant intensity approximation (CIA), in contrast to the constant field approximation (CFA), an additional term \(\Gamma_{i}^{2}\sim I_{i0}\) appears, which leads to increase in the threshold pump intensity. We present a numerical estimate of the threshold intensity for KTP along with a comparison with the experiment. The results hint at a research method that holds promise for the development of efficient parametric frequency converters for visual observation of biological objects and in medical research.