Modeling and Characterization of High-Efficiency, High Power Cascaded Intracavity Optical Parametric Oscillators in the Mid-Infrared

We report on the modeling and demonstration of an efficient intracavity cascaded PPLN OPO which converts 20% energy from 1.064 µm to three narrow bands in the 2-5 µ wavelength range. We have fully modeled the power, pulse shape, spectrum of each wavelength involved in the cascaded optical parametric processes. Spatio-temporal numerical simulation of these processes combined with simple thermal models provide a correct estimate of the selfinduced thermal lensing and efficiency saturation.