The First Coupling of a Laser Beam to a Water Jet

Abstract Assigned to a project for designing a laser‐based dental hand tool, Bernold Richerzhagen visualized combining a water jet and a laser for tooth ablation. His dental tool envisioned a laser within a low‐pressure hair‐thin water jet that guided the beam by means of total internal reflection in a manner like an optical fiber. Eventually, this fusion of light and water resulted in a new technology capable of machining hard materials with high precision. Starting with a dental tool developed in a Swiss laboratory in 1993, this invention has fostered high‐precision laser machining in the aviation, diamond and semiconductor industries amongst others.