Fabrication of waveguides in LiTaO₃ by using femtosecond laser pulses

Abstract

Optical waveguides were fabricated in the LiTaO₃ (LT) single crystal by irradiating focused femtosecond laser. The laser induced structures in three kinds of materials (two different compositions of LT, and congruent LiNbO₃ for compare) were studied. The cross sections of the structures and waveguiding behaviors were strongly dependent on the kind of the material, focusing depth, repetition frequency, and pulse duration. The waveguide with comparatively less polarized light dependancy was formed in congruent LT at pulse duration of 64fs, repetition rate of 250kHz, pulse energy of 2.0μJ, focusing depth of 50μm, and scanning speed of 500μm/s.