Figure 4
From: Spatially controlled nano-structuring of silicon with femtosecond vortex pulses
Fabrication of complex nanostructures. Mapping of complex intensity profiles generated by VVB produced by two q-plates with topological charge of \(q=-1\), and \(q=1/2\). (a) A HWP between the \(q=-1\) (\(\ell = \pm 2\)) plate and a detuned \(q=1/2\) (\(\ell = \pm 1\)) plate, and (b) without the HWP between the two q-plates. The corresponding calculated intensity profiles are shown in (c, d). Experimental patterns were produced by a single pulse with an energy of 700 nJ.
