Ultrafast Laser Micromachining of Nanoparticle-Embedded Resins for the Direct Fabrication of Atom Probe Tomography Specimens

Atom probe tomography (APT) enables three-dimensional, near-atomic-scale compositional analysis of nanomaterials; however, its application to individual nanoparticles (NPs) remains limited due to the complexity of specimen preparation, including lift-out procedures and precise apex shaping. In this work, we investigate ultrafast laser micromachining of NP-embedded resin composites to develop a protocol for the direct, site-specific fabrication of APT specimens without the need for lift-outs. Finite element simulations of laser processing reveal that increasing the NP concentration significantly enhances optical absorption, expanding the heat-affected zone from 5 to 20 μm within the resin composite. As a proof of concept, tip arrays containing embedded spinel ferrite NPs are laser micromachined on a resin half-grid with minimal thermal damage and subsequently polished using focused ion beam milling. APT analysis of these specimens yields a high number of detections from both the resin matrix and the NPs, enabling reconstruction of distinct oxide isosurfaces and detailed compositional mapping. Overall, this study highlights the potential of laser-based preparation as a practical alternative route for enabling APT analysis of nanoparticle-embedded systems.