Figure 5. Analysis of the nanofocus spot size of the Ir-filled diamond FZP.

(a) The squared imprint diameters as a function the logarithm of the pulse energy reveals two regions that can be approximated by straight lines corresponding to a double-Gaussian spot with sigma-values of 120 nm and 350 nm, respectively. (b) Beam profile derived from the same data set. The left y-axis shows the inverse pulse energies of the individual shots. The right y-axis is normalised such that the integral energy over the analytical double-Gaussian function is equal to E_max = 5×10⁻⁵ J (see methods).