Abrupt transition from wavelength structure to subwavelength structure in a single-crystal superalloy induced by femtosecond laser

▶ Transition from wavelength structure (LSFL) to subwavelength structure (HSFL). ▶ Transition is initiated by generation of new grooves on main ridges of LSFL ripples. ▶ Relationship between structures and their parametric dependence is established. ▶ Second harmonic generation is responsible for the formation of HSFL.