Femtosecond Laser Direct Writing for Polarization Convertors and Geometric Phase Elements

There is a growing popularity of the miniaturization and integration of various optical elements. In particular, the meta-optics has attracted great interests by manupulating the electric-magnectic properties of materials. Herein, we reviewed the recent advances on the fabrication and characterization of polarization convertors and geometric phase elements by femtosecond laser direct wirting. Firstly, the mechanism of meta-optics will provide. Then,we will review the fabrication technologies for meta-optics by femtseond laser direct writing in photoresist,laser ablation on metal film, and femtosecond laser-induced nanogratings in the bulk. Finally, we will comment on the challenges of femtosecond laser micro/nanotechnologies for meta-optics.