Efficient generation of 13–30 microns based on parametric conversion in periodically-poled LiNbO3 under surface-emitting geometry

The authors present our new results following our investigation of mid-IR and far-IR generation at the polariton resonances of a PPLN crystal. The efficient conversion is made possible by using a novel configuration, i.e. surface-emitting geometry. The authors first proposed to use such a configuration to achieve parametric oscillation and amplification in the near-IR and mid-IR domains. It was also used to generate THz waves from a PPLN crystal. However, since the output frequencies were far away from the polariton resonances, the output powers obtained previously were below the nW level.