Domain reversal properties and refractive index changes of magnesium doped lithium niobate upon ion exposure

Irradiation of optical damage resistant, magnesium doped lithium niobate crystals with fast, high-energy He2+3 ions changes important material properties. In the interaction region, where the ions transmit through the material, the ferroelectric coercive field EC is diminished from 6.0kVmm−1 down to 5.0–5.4kVmm−1 after transmission of 41MeV He2+3 particles. This enables easier domain reversal in irradiated crystals compared to untreated material. Besides, large changes of the refractive index of the crystals on the order of 6×10−3 are induced by the treatment. Moderate annealing treatments do not diminish Δn, but refresh the coercive field.