Refractive index modulation of YAG crystal through electronic energy depositions of argon ions

This work has demonstrated the feasibility to modulate the refractive index of YAG crystal at variable depths via electronic energy depositions of argon ions. Surface and buried cladding waveguide layers of various geometries were successfully created, which are capable of effective light confinement and guidance at infrared waveband of 1064 nm. Refractive index profiles of irradiated layers were reconstructed in a reasonable manner according to the variations of electronic stopping powers. Information about the structural damage level of ion irradiated crystal were given by measured micro-Raman spectra and signal intensity dependence on penetration depth. Ridge waveguides with superior guiding performances were also manufactured on the platform of refractive index modulated crystals. Based on the precise index modulation shown in this work, extended applications of active ion doped YAG waveguides with better performances, such as high-efficiency waveguide laser oscillation and high-gain integrated optical signal amplification, could be expected.