Abstract
An attempt has been made to manufacture a recursive mirror for the optical measurement of soundness of a mercury-target vessel that is to be installed in the J-PARC project at the JAEA. The mirror is comprised ofdozens of reentrant pyramids as large as about 100μm in length. In order to make such a micro shape directly on a stainless steel substrate, we modified a pulsed Nd:YAG laser with 1.06μm wavelength to achieve resolutions of 10μm in width and 1μm in depth for the laser ablation. Its feasibility has been confirmed by manufacturing a small triangle as large as about 50μm in width and about 1μm in depth under the conditions of a scanning speed of 1mm/min, a voltage of 272 V, and a hatching width of 2μm.
