Control of laser machining of polycrystalline diamond plates by the method of low-coherence optical interferometry

The possibility of applying low-coherence fibre optics interferometry for local contactless measurement of the optical thickness of polycrystalline diamond plates during high-power laser-pulse processing of their rough surface is demonstrated. A unique automated experimental system is developed to control the thickness of samples during ablation of their surface by a scanning 248-nm KrF excimer laser beam. It is shown that this technique is suitable for on-line control of laser polishing and for preparing plane-parallel plates.