Damage evolution and waveguide formation in SrTiO3 crystal irradiated by tens of MeV Si ions

In this work, lattice damage behavior and optical waveguide formation in SrTiO3 crystal induced by swift ion irradiation have been studied. SrTiO3 crystal with (1 0 0) surface normal zone axis direction has been irradiated by 20 MeV Si3+ ions with a fluence of 1 × 1015 cm−2 at 300 K. Subsequently, structural damage induced by nuclear or electronic energy loss processes along ion penetration path has been analyzed by complementary characterization techniques, and the results indicate that the produced lattice damage in this case should be attributed to the nuclear energy loss. Utilizing the change of refractive index in lattice damage region, waveguide structure has been successfully prepared and the related optical properties have been studied through various coupling techniques. The iWKB (inverse Wentzel-Kramers-Brillouin)-reconstructed refractive-index profile of irradiation region appears reasonable correspondence (symmetrical inversion) with SRIM-simulated dpa profile, which also proves that lattice damage and waveguide formation in SrTiO3 should be ascribed to the nuclear energy loss during tens of MeV Si-ion irradiation process.