Figure 1. Fabrication of multi-microholes by the fs PVOFs composed of four individual linearly-polarized scalar fields with m = 0 and a = 1.0 mm.

(a) and (b) are the two PVOFs composed of four individual linearly-polarized scalar fields, which arrange a square, where the arrows show the SoP configurations. (c) shows the simulated Airy spot of the focused individual field. (d) is the simulated interference pattern with a tetragonal lattice of four individual fields. (e) indicates the simulated pattern of the focused PVOF, which contains four bright spots. (c)–(e) have a dimension of 60 × 60 μm². (f) is the SEM image of the multi-microholes fabricated by 50 pulses at a fluence of about 6.9 J/cm².