Thin-Glass Microhole Etching with Ring-Shaped Laser Beam Shaping

A diffractive optical element is introduced as an intermediary component between the laser source and the glass substrate. This DOE shapes the laser beam into a Bessel beam profile, enabling precise microhole formation in thin glass without requiring complex mechanical or optical systems. The intermediary element transforms the conventional Gaussian beam into a structured light field that maintains its shape during propagation, achieving high precision while keeping the overall system relatively simple.

The patent replaces complex mechanical optical setups with a diffractive optical element that generates Bessel beams through optical diffraction principles. Instead of using multiple lenses, mirrors, and adjustment mechanisms to create elongated focus distributions, the DOE uses interference and diffraction of light to self-form a Bessel beam profile that naturally maintains its shape over an extended propagation distance, simplifying the optical system while achieving the desired elongated modification.

The laser processing step is designed to create a precise cylindrical modification pattern that serves as a pre-prepared template for the subsequent etching process. By using Bessel beam-induced modifications with controlled geometry and distribution, the preliminary laser action defines the exact microhole shape and position, allowing the wet-chemical etching to proceed efficiently with minimal additional time while maintaining high precision. The preliminary structured modification enables selective and rapid etching.