Tunable Quasi-Phase Matching using Dynamic Ferroelectric Domain Gratings Inducedby Photorefractive Space-Charge Fields

摘要

We demonstrate a method of dynamic, tunable quasiphase matched second harmonicgeneration using optically induced polarization gratings with periods equal to twice the coherence length. These gratings increase the peak second harmonic conversion efficiency by a factor of 17 above a poled strontium barium niobate crystal, to 0.01% for fundamental beam intensities of 0.8 Mw cm-2. We generate quasiphase matching spectral response peaks as narrow as 0.175 nm and tailor the response by writing an ensemble of gratings in the same volume, each of which enhances the second harmonic generation at a predetermined wavelength.