Waveguide formation of KTiOPO₄ by multienergy MeV He⁺ implantation

X-cut potassium titanyl phosphate (KTiOPO₄ or KTP) was implanted by multienergy MeV He⁺ implantation with a total dose of 2 × 10¹⁶ ions/cm² at liquid nitrogen temperature. The energy and dose used are as follows: 3.3 MeV and 2 × 10¹⁵ ions/cm², 3.2 MeV and 4 × 10¹⁵ ions/cm², 3.1 MeV and 4 × 10¹⁵ ions/cm², and 3.0 MeV and 1.0 × 10¹⁶ ions/cm² to reduce tunneling effect. The 22 dark modes were measured by the isosceles prism coupling method. The 15 bright modes were observed after 250 °C, 60 min annealing. The result shows that the waveguide formation of KTiOPO₄ implanted by MeV He⁺ is not strongly dependent on the cut direction, which is different from the waveguide formation of KTiOPO4 by ion exchange process.