In this study, we investigate the spatial distribution and dynamics of neutral gold atoms (Au I) immediately following spark generation using a structured two-photon laser-induced fluorescence (TALIF) technique, dubbed Light Amplitude Control (LAC). Ultrashort laser pulses with tailored spectral and spatial profiles excite gold’s atomic transitions, with fluorescence signals processed via multi-dimensional lock-in detection. The research examines spark ablation for nanoparticle synthesis by linking gold vapor cloud evolution with SDG parameters. Experiments using Au and Cu electrodes, high-speed imaging, and SMPS measurements reveal how spark energy, repetition frequency, gas composition, and flow rates critically govern early nucleation and particle growth.

This study examines the oxidation mechanism of Co-Ni nanoparticles synthesized via spark ablation to optimize NiCo₂O₄ for catalytic applications. A spark discharge generator (SDG) produced three precursor structures in air, nitrogen, and nitrogen/hydrogen. X-ray diffraction (XRD) confirmed the formation of NiCo₂ in metallic and oxide phases but not NiCo₂O₄. Annealing at 450°C converted these precursors into NiCo₂O₄ with structural variations. In-situ environmental TEM (ETEM) provided real-time insights into oxidation, revealing void formation that increases surface area and enhances catalytic performance. Understanding these mechanisms helps refine synthesis conditions for improved material properties.

This study investigates the composition evolution of Cu-Zn nanoparticles (NPs) produced via spark ablation, challenging the assumption that NPs retain the feedstock’s composition when produced using alloyed feedstocks. Preliminary findings reveal depletion of Zn in the feedstock surface, indicating compositional shifts in the generated NPs—likely driven by differences in melting point and vapor pressure between Cu and Zn.
Using time-resolved x-ray fluorescence, ICP-MS, and optical emission spectroscopy, we analyze NPs from Cu-Zn alloys and pure elements. These results provide new insights into spark ablation dynamics, enabling better control over bimetallic NP synthesis, of great improtance in catalysis and sensing applications.

Antennas are primarily designed to receive and transmit electromagnetic (EM) waves, spurring widespread applications in communications, radars, and radios. However, traditional nanofabrication techniques generally suffer from 2D flat patterns. This not only increases energy dissipation but also eliminates the possibility for three-dimensional control. To resolve that, we used our homemade printer for fabricating 3D plasmonic nanoantennas with various material combinations (Au, Ag, and their hybrids) and dimensional flexibilities, showcasing tunable responses to visible light.