Superhydrophobic silicon surface fabricated by femtosecond laser ablation in the atmosphere. (a–d) SEM images of the femtosecond laser-ablated silicon surface: (a) side view, (b) top view, (c) higher resolution image, and (d) cross-sectional image. (e, f) Shape of a small water droplet on the superhydrophobic silicon surface. Reproduced from [101
] with the permission.