Reducing the pyroelectric effect in lithium niobate Q-switch crystals

摘要

The influences of thermo-chemical reduction processing on the physical properties of lithium niobate are studied. The behavior of the surface resistivity and the induced optical absorption are characterized, with trends indicating a significant reduction in resistivity can be realized before absorption becomes problematic in the 1.0 μm spectral region. The edge localization of the effects in bulk materials is identified, suggesting a central clear aperture of high transmission is possible even when large absorption near the crystal edges is observed. Electro-optical Q-switch crystals were processed with varying degrees of annealing and reduction, leading to the realization of several samples with optimal combinations of modified surface and bulk properties. The highest transmission samples were then tested under transient ambient temperature conditions and compared to unprocessed crystals. The processed samples showed a significant reduction in the transient depolarization of transmitted laser light due to the pyroelectric effect.