Reversible microstructuring of lithium niobate by direct laser write technique

Versatility of femtosecond direct laser writing (DLW) technique for non-destructive and reversible micro-structuring of lithium niobate crystals is demonstrated. Persistent photorefractive modification induced by the focused laser beam without structural damage to the host crystal has refractive index modulation on the order of 10-5-10-2, and can be optically erased or modified. Application of this mechanism for realization of diffractive optical elements is demonstrated.