Some current research in femtosecond laser-induced surface ripple structures

Some current research in femtosecond (fs) laser induced surface nano/micro structures on compound semiconductors is discussed in this paper. Both wavelength and sub-wavelength periodic surface structures were observed on InP and GaN/sapphire surfaces irradiated with fs laser pulses. It was found that the morphology of the periodic structure was dependent on the polarisation of the laser beam and the number of laser pulses, and the period was dependent on the incident laser fluence. Through finely adjusting laser fluence and pulse number, uniform ripples can be achieved. The mechanisms involved in the formation laser induced surface structures are also discussed.