Figure 2.

(a,c,e) SEM images of processed surface and a twisted nanoneedle fabricated by an optical vortex with a total angular momentum J of −2 (clockwise). (b,d,f) SEM images of processed surface and a twisted nanoneedle fabricated by optical vortex with a total angular momentum J of 2 (counter-clockwise). (c,d) The 25° views and (e,f) top views of the nanoneedle. (g) The 25° view of the nanoneedle formed using a pulse energy of 2 mJ. The chirality of the fabricated nanoneedle disappears. The focusing lens had an NA of 0.08. We estimated the tip curvature by fitting the tip with a circle utilizing software installed on the SEM, as shown in (h). The uncertainty in the measured values is approximately ±15%.