Multienergy Cu<sup>+</sup> ions with total dose of ~10<sup>14</sup> ions/cm<sup>2</sup> were implanted into LiNbO<sub>3</sub> crystals to form a nearly homogenous damage profile from the sample surface to the end of the ions’ track. The extraordinary refractive-index enhancement was found in the damage region by observation of the dark mode. The extraordinary index showed an increasing trend until the ion dose reached a critical value. The largest index enhancement was ~0.0132. By use of low-dose ion implantation, we determined that the decreased spontaneous polarization caused the extraordinary index increase.
© 2001 Optical Society of America
Hui Hu, Fei Lu, Feng Chen, Bo-Rong Shi, Ke-Ming Wang, and Ding-Yu Shen, "Extraordinary Refractive-Index Increase in Lithium Niobate Caused by Low-Dose Ion Implantation," Appl. Opt. 40, 3759-3761 (2001)