Analysis of formation mechanism of microspike-arrays on tungsten surface by femtosecond laser irradiation

Abstract

Microspike–arrays are formed on tungsten surface by irradiating femtosecond laser through a mask opening in the air. The formation mechanism of such microspike–arrays was discussed with analysis of laser light diffraction. Intensity distribution diffracted through a mask opening was calculated by using the Fresnel–Kirchhoff diffraction integral, not the equation of Fresnel diffraction, because the distance from a mask to tungsten is almost as short as the size of a mask opening. Estimated ablation results by repetitive irradiation were consistent with the experimental results. Microspike–arrays have potential in application for such as emission cathodes in a Field Emission Display(FED).