Dielectric function and the crystal structure of MeV ion implanted LiNbO3

► 3.1 MeV Au-ion implantation strongly affected LiNbO3 crystal on the complex dielectric function of from 1.2 to 21 THz. ► The dielectric function reflected the optical phonon modes, so that the change in the function revealed the change of lattice structure. ► The ion implantation caused the amorphization at the fluence of over 1013 cm-2. ► The amorphization was accompanied with volume expansion of about 8%.