Formation Dynamics of Periodic Surface Patterns in Ge Induced by UV Nanosecond Laser Pulses

Direct Laser Interference Patterning (DLIP) is a versatile technique that enables the single pulse fabrication of periodic surface structures over relatively large areas in a variety of materials [1], [2]. The sinusoidal shape of the intensity profile cross sections at the sample surface created by two or more interfering laser pulses triggers the formation of periodic surface patterns, whose periodicity can be tuned by modifying the irradiation configuration. In that sense, DLIP can be considered to belong to the larger category of laser induced periodic surface structures (LIPSS) fabrication strategies, with the added benefit of single pulse operation, tunable period, highly homogeneous feature shapes and orientations for a wider range of materials.