Multi-pulse agglomeration effects on ultrashort pulsed direct laser interference patterning of Cu

Abstract

Surface functionalization by biomimetic patterns in the micro- and nanometer scale is well-established in a wide range of applications. The finely tuned surface properties are directly related to both primary and sub-pattern morphology of the applied topographies, which must be well-adjusted for maximum functionalization effi ciency. In this light, the role of proceeding surface modification and its effect on pattern formation alongside multi-pulse ultrashort pulsed direct laser interference patterning (USP-DLIP) of Cu are investigated in detail by applying a multi-method characterization approach. It was shown that aside of topographical remodeling, USP DLIP processing parallelly affects chemistry and the mechanical deformation state of the substrate surface, which in turn considerably influences laser/material interaction via incubation. An in-depth investigation of the in dividual and combined impacts of these substrate alterations on localized optical absorptance reveals how pri mary and sub-pattern formation dynamically respond to process induced surface modification. The DLIP-specific incubation impact on pattern morphology increases with inverted relation to pattern scale. The findings of this study provide a profound insight in the predominant physical interactions involved in pattern formation arising from the mutual influence between laser irradiation and substrate modification during USP-DLIP-processing of Cu allowing for high precision micro- and nanometer scaled pattern design.