Picosecond laser ablation of millimeter-wave subwavelength structures on alumina and sapphire

•100 W ps-laser ablation of mm-wave subwavelength structures on alumina and sapphire.•Average ablation rate larger than 20 mm3/min on alumina and sapphire.•Order of magnitude increase in average ablation rate of alumina and sapphire.•Modeling of ultrashort-pulse laser ablation for fabricating pyramid structures.