Laser-guided anisotropic etching for precision machining of micro-engineered glass components

Abstract

Micro-engineered glass components play a vital role in various domains, but their full potential remains untapped due to the lack of easily accessible high-precision machining methods for customizable microstructure. Our discovery of a new phenomenon, where laser-modified regions break the rule of inherently isotropic glass etching and regulate a directional anisotropic etching along modified tracks, has led to the development of a laser-guided anisotropic etching (LGAE) method. This method enables crafting precision glass microstructures with sharp features, smooth surfaces, and adjustable shapes and sizes. An ultrafast Bessel beam is utilized to create high aspect-ratio line-shaped modification within the glass. With a higher etching rate than pristine glass, the modified line guides directional anisotropic etching along the modified track, facilitating the formation of a V-shape with an angle altered by the etching ratio. These modified lines can further serve as basic building blocks to interconnect to construct a 3D internal modification region and then guide the glass's overall surface morphology etching evolution, enabling the creation of microstructures featuring designable shapes and adjustable feature sizes. To accurately predict and control the shape of the microstructures, we establish a finite difference etching model that incorporates localized etching rate regulation, validating the robustness and controllability of LGAE. This scalable method has successfully fabricated a 50 μm period micro-pyramid array with high uniformity over a centimeter-scale area, demonstrating its suitability for large-scale manufacturing. The showcased micro-engineered glass components encompass V-groove arrays for fiber alignment, blazed gratings for light modulation, and microchannels with customized trajectories for microfluidic chips. These advancements driven by LGAE can significantly contribute to the progress of glass-based research and industries.