Ultrafast Laser Filamentation in Semiconductors

Ultrafast laser filamentation is an extremely nonlinear propagation phenomenon that can be advantageously used in transparent media for countless applications [1]. In contrast, in semiconductors which exhibit extreme nonlinear refractive indices, delocalization of energy deposition as well as intensity clamping represent major challenges for precise in-volume ultrafast processing [2,3]. To date, the overwhelming majority of studies on ultrafast laser filamentation in semiconductors is restricted to silicon. Understanding filamentation inside this material has led to the development of innovative functionalization techniques, as exemplified with transmission welding [4,5], transverse inscription for wafer dicing [6], backside amorphization [7], and waveguide writing [8,9]. However, ultrafast laser filamentation in other semiconductors remains uncharted to date, despite the fact that its exploration could lead to similar developments in these materials.