飞秒激光直写是一种高效灵活的三维精密材料加工技术,在许多领域得到了广泛的应用。光波导是集成光子学器件的一种基本结构,能够将光场限制在微小的通道内进行无衍射的传输。激光晶体是全固态激光器的常用增益介质,利用飞秒激光直写技术在激光晶体上构建光波导结构,并保持晶体的原有属性,从而可以制备低成本、高效率的波导激光器件。从飞秒激光诱导晶体产生的两类结构改性(折射率改变)出发,综述了飞秒激光直写激光晶体光波导的种类、特性以及应用,并对相关领域的应用前景进行了展望。

Femtosecond laser direct writing is a highly efficient and flexible three-dimensional processing technique with high precision, which is widely used in many fields. Optical waveguide that confines light propagation in microscale channels is one of the basic components in integrated photonic devices. Laser crystals are major gain media for all-solid state lasers. The femtosecond laser direct writing that constructs the optical waveguides in laser crystals preserves the original features of bulks, and can prepare low-cost and high efficiency waveguide laser devices. Starting from two types of femtosecond laser induced structural modifications (with refractive index change) in crystal, this work reviews the categories, characteristics, and applications of laser crystal optical waveguides fabricated by the femtosecond laser direct writing. The application prospects in relevant fields are also presented.