Chemical control of optical damage in lithium niobate

A new chemical process has been developed that significantly affects the susceptibility of LiNbO3 crystals and optical waveguiding layers to the laser-induced effects known as optical damage. The process involves controlling the nonstoichiometry of LiNbO3 by diffusion of lithium oxide. Susceptibility to optical damage in bulk crystals was reduced by increasing the nonstoichiometry (out-diffusion) and enhanced by decreasing the nonstoichiometry (in-diffusion). Typically, low-loss optical waveguides formed by the process supported one or more TE modes and tolerated more than 10 kW/cm2 laser transmission at 488.0 nm without inducing any measurable beam profile distortion.