Irradiation of lithium niobate crystals with 41 MeV <sup>3</sup>He ions causes strong changes of the ordinary and extraordinary refractive indexes. We present a detailed study of this effect. Small fluence of irradiation already yields refractive index changes about 5×10<sup>−4</sup>; the highest values reach 3×10<sup>−3</sup>. These index modulations are stable up to 100°C and can be erased thermally, for which temperatures up to 500°C are required. A direct correlation between the refractive index changes and the produced lattice vacancies is found.
© 2006 Optical Society of America
Original Manuscript: March 27, 2006
Revised Manuscript: June 13, 2006
Manuscript Accepted: June 23, 2006
Konrad Peithmann, Mohammad-Reza Zamani-Meymian, Matz Haaks, Karl Maier, Birk Andreas, and Ingo Breunig, "Refractive index changes in lithium niobate crystals by high-energy particle radiation," J. Opt. Soc. Am. B 23, 2107-2112 (2006)