Laser-Induced Cavitation-Assisted True 3D Nano-Sculpturing of Hard Materials

Femtosecond lasers enable flexible and thermal-damage-free ablation of solid materials and are expected to play a critical role in high-precision cutting, drilling, and shaping of electronic chips, display panels, and industrial parts. Although the potential applications are theoretically predicted, true 3D nano-sculpturing of solids such as glasses and crystals, has not yet been demonstrated, owing to the technical challenge of negative cumulative effects of surface changes and debris accumulation on the delivery of laser pulses and subsequent material removal during direct-write ablation. Here, a femtosecond laser-induced cavitation-assisted true 3D nano-sculpturing technique based on the ingenious combination of cavitation dynamics and backside ablation is proposed to achieve stable clear-field point-by-point material removal in real time for precise 3D subtractive fabrication on various difficult-to-process materials. As a result, 3D devices including free-form silica lenses, micro-statue with vivid facial features, and rotatable sapphire micro-mechanical turbine, all with surface roughness less than 10 nm are readily produced. The true 3D processing capability can immediately enable novel structural and functional micro-nano optics and non-silicon micro-electro-mechanical systems based on various hard solids.

Automated summary

Femtosecond lasers enable flexible and thermal-damage-free ablation of solid materials, but true 3D nano-sculpturing has not been achieved due to technical challenges. This article proposes a new technique using cavitation dynamics and backside ablation to achieve stable material removal for precise 3D fabrication. With this technique, 3D devices with surface roughness less than 10 nm can be produced, enabling novel structural and functional micro-nano optics and non-silicon micro-electro-mechanical systems.