Restoration of blurred images due to phase distortion based on polarization-insensitive phase conjugation in second-order nonlinear medium.

Broadband and polarization-insensitive phase conjugation, achieved based on difference-frequency generation in a second-order nonlinear composite consisting of stacked KTiOPO(4) (KTP) plates, was exploited to restore blurred images due to phase distortion as a novel scheme. Due to the quasi-phase matching in the stacked KTP crystals, our result reveals that the image restoration is insensitive to the polarization direction and wavelength of the input beam.

Efficient generation of far-infrared radiation in the vicinity of polariton resonance of lithium niobate.

We efficiently generated far-infrared radiation at the wavelengths centered at 20.8 µm in the vicinity of one of the polariton resonances of lithium niobate. Such an efficient nonlinear conversion is made possible by exploiting phase matching for difference-frequency generation in lithium niobate. The highest peak power reached 233 W.