SLM. The color code features a blue channel representing the amplitude modulation from 0 (black) to 1 (blue) and a green channel corresponding to phase modulations from 0 (black) to $2\pi$ (green). Next, we conclude from the measured relative spot size $w/w_\text{B}$ that the spot size decreases if the ROI size is reduced. The reduced spot size is achieved at the expense of the spot intensity which is redistributed to a ring outside of the ROI similar to the theoretical results presented in section \[s:sec34\] and Fig. \[fig7\]. Referring to the Exp-S data, for $R = 7\,\text{pixel}$ the spot size is reduced to $72\,\%$ of the size of the reference Bessel beam’s core and even further to $50\,\%$ for $R = 4\,\text{pixel}$. The latter result is somewhat vague, though, due to the low spot intensity which may be truncated by the sensitivity threshold of the CCD detector and thus may appear smaller. However, our experimental results overall clearly verify the OEi concept applied to spot size minimization. Moreover, the results strongly suggest that the OEi optimization may indeed squeeze spots to the subdiffractive regime since the optimal superposition of Bessel beams not only beats the Airy disk but also the 