Optical and Magnetic Microstructures in YIG Ferrite Fabricated by Femtosecond Laser

Optical and magnetic microstructures are directly fabricated inside a film of cerium-substituted yttrium iron garnet (Ce:YIG) by using a direct femtosecond laser writing. The laser irradiation in-duces local changes in both optical and magnetic properties of Ce:YIG. A quantitative phase imag-ing technique proves that the refractive index is increased by 0.015 ± 0.001, which is about 0.7 % of Ce:YIG refrative index 2.2 at 632.8 nm. The magneto-optical polar Kerr effect measurement shows that the magnetization property is changed from hard to soft, decreasing the coercivity. Our pro-posed technique paves the way toward the development of novel three-dimensional magneto-optical devices for optical communication and photonic applications