Barrier Optical Waveguide Formation in La₃Ga₅SiO₁₄ Crystals by High Energy Carbon Ion Implantation

The barrier planar waveguides are fabricated for the first time in z-cut LGS (La₃Ga₅SiO₁₄) crystals by 3.0 MeV and 6.0 MeV carbon ion implantations with dose of 2 x 10¹⁵ions/cm² at room temperature. Four and six dark modes were observed by the prism-coupling method, respectively. The refractive index profiles were reconstructed by using the reflectivity calculation method. There are about 1.6% and 0.9% decreases at the optical barriers in the 3.0 MeV and 6.0 MeV cases, and the positions of the optical barriers are close to that of the damage peaks calculated by the TRIM'98 (Transport of Ions in Matter) code. It is found that the refractive index change may partly be due to the damage induced by the nuclear collision.