Controllable annulus micro-/nanostructures on copper fabricated ...

In this study, we propose an effective method for the fabrication of annulus micro-/nanostructures by a femtosecond laser doughnut beam. Compared with the traditional Bessel annulus beam shaping system, this method greatly compresses the light propagation path. It is theoretically and experimentally demonstrated that the obtained axial section of the peak envelope in the processing area is two waists of the isosceles triangle. By moving the relative position of the sample, annulus microstructure