Femtosecond laser-induced periodic surface structures on hard and brittle materials

Hard and brittle materials have high hardness, excellent optical stability, chemical stability, and high thermal stability. Hence, they have huge application potential in various fields, such as optical components, substrate materials, and quantum information, especially under harsh conditions, such as high temperatures and high pressures. Femtosecond laser direct writing technology has greatly promoted the development of femtosecond laser-induced periodic surface structure (Fs-LIPSS or LIPSS by a femtosecond laser) applications of hard and brittle materials due to its high precision, controllability, and three-dimensional processing ability. Thus far, LIPSSs have been widely used in material surface treatment, optoelectronic devices, and micro-mechanics. However, a consensus has not been reached regarding the formation mechanism of LIPSSs on hard and brittle materials. In this paper, three widely accepted LIPSS formation mechanisms are introduced, and the characteristics and applications of LIPSSs on diamonds, silicon, silicon carbide, and fused silica surfaces in recent years are summarized. In addition, the application prospects and challenges of LIPSSs on hard and brittle materials by a femtosecond laser are discussed.