Reduction of the Susceptibility to Optically Induced Index Inhomogeneities in LiTaO3 and LiNbO3

Abstract

It has been established that LiTaO₃ can be made resistant to laser‐induced inhomogeneities in the index of refraction at power levels as high as 500 W/cm². This is accomplished by annealing LiTaO₃ in an electric field of 250 V/cm at a temperature of 700°C for ½ h and then cooling the crystal to room temperature with the field on at a rate of 100°C/h. The susceptibility to laser‐induced index changes in LiNbO₃ is reduced by this treatment but not to the same extent as in LiTaO₃. A mechanism is proposed to explain the observed reduction in susceptibility to damage.