Quasi-phase-matched second-harmonic generation of blue light in periodically poled LiNbO3

Abstract

LiNbO₃ crystals with periodically alternating ferroelectric domains have been produced using laser‐heated pedestal growth. Domain thicknesses as small as 1 μm have been achieved. This material was applied to room‐temperature, quasi‐phase‐matched frequency doubling to generate light at wavelengths as short as 407 nm, using the d₃₃ and d₂₂ nonlinear coefficients. The measured conversion efficiencies and wavelength and temperature tuning bandwidths are consistent with an effective interaction length of ≊320 μm (>230 domains). An initial test with high‐intensity focused blue beams showed that the periodically poled material exhibits no discernible photorefractive damage effect.