Figure 5.

(a) SEM image of the Si–Cr alloy disk formed on the Cr film (30 nm), imaged after Cr-etch. Pulse energy $E_p=3$ nJ. (b) SEM images of Si-Cr disks used as dry plasma etch mask followed by Cr-etch. (c) SEM image of Si-Cr rings used as dry plasma etch mask followed by Cr-etch. Laser patterning was carried out with $NA=0.75$; diffraction limited focal diameter $1.22\lambda /NA=838$ nm; wavelength $\lambda =515$ nm. Plasma etch was for 5 min.