Evolution of optical absorption and strain in LiTaO3 crystal implanted by energetic He-ion

Z-cut LiTaO3 single crystal wafers were implanted at room temperature by 100-500 keV He-ion, to fluences in the range from 1.0 × 1015 to 1.0 × 1017 ions/cm2. The implanted samples were characterized by UV/VIS/NIR Spectrometer, and XRD technique. Optical absorption occurred in all implanted LiTaO3, but to different extent. Optical absorption apparently depends on both the fluence and energy of ions. The damage caused by ion implantation in LiTaO3 is not the only factor for the optical absorption. XRD measurement shows that there is also a large implantation induced strain in the samples which have strong optical absorption. And the release of strain is always companied by the recovery of optical absorption. Stress might play an important role in the optical absorption.