Deep-subwavelength nanohole arrays embedded in nanoripples fabricated by femtosecond laser irradiation.

We report on the formation of deep-subwavelength nanohole arrays embedded in silicon carbide nanoripples fabricated by an 800 nm femtosecond laser in an underwater environment. The period of the nanoripples is about 500 nm. The ripples are perpendicular to the polarization direction of the incident laser. The diameter of the holes is about 30 nm, and the period of the hole array is about 60 nm. Nanoripple formation is attributed to interference of the incident laser and a laser-induced plasma wave. Nanohole array formation is attributed to the formation of channel plasmon polaritons in the laser-induced nanogrooves associated with the nanoripples.