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 induces local changes in both optical and magnetic properties of Ce:YIG. A quantitative phase imaging 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 proposed technique paves the way toward the development of novel three-dimensional magneto-optical devices for optical communication and photonic applications.