ERASING PROCESS OF THERMALLY POLED OPTICAL NONLINEARITIES IN SILICA GLASSES WITH KRF EXCIMER-LASER PULSES

We observed a second-order optical nonlinearity of chi(33)((2))=0.30 p m/V in a fused silica glass poled under the condition of static electr ic field of 4 kV/mm at 260 degrees C. The nonlinearity layer localized in die surface region contacted on the positive electrode during poli ng in a thickness comparable with or thinner than the interaction leng th of 22 mu m. Even though a nonlinearity phase formation was not obse rved hi synthetic silica glass under the same condition, the poling in duced a nonlinearity of 0.24 pm/V by exposing the sample to X-ray radi ation before poling. We also observed that 248-nm pulses as low as 10 mJ/cm(2) from a KrF excimer laser erased die nonlinearity.