Mid-infrared radiation in an aperiodically poled LiNbO3 superlattice induced by cascaded parametric processes

Abstract

The cascaded parametric processes, i.e. optical parametric oscillation (OPO) and difference frequency generation (DFG), can be used to induce efficient CW mid-infrared radiation at 4-5 μm in a single optical superlattice obtained by aperiodically poling a ferroelectric crystal. The superlattice consists of basic building blocks modulated by a spatial function. We numerically solve the coupling equations considering pump depletion and mid-IR absorption and realize the optimal condition for the cascaded frequency-down-conversion processes. Simultaneously, it is seen that the output performance is enhanced by the cascaded parametric design compared to the standard OPO configuration.