His invention was based on the fusion of laser and water to drill tooth enamel. The laser beam was guided by total reflection within a fine water jet in the manner of an optical fiber. The laser provided the heat for ablation while the water cooled the material. This water jet-guided laser offered the advantage of a parallel cylindrical laser beam without any beam divergence that is inherent in other laser processes.After four years of extensive trials, Richerzhagen succeeded in coupling a high-power laser beam in a hair-thin water jet.
Richerzhagen obtained his doctorate in 1994. That same year and in the following years he was awarded patents for his water jet-guided laser beam process by the German and Europea patent offices.
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