Fig. 2: Diffractive all-optical transformations and their differences from the ground truth, target transformation (A) presented in Fig. 1b.
From: All-optical synthesis of an arbitrary linear transformation using diffractive surfaces
\(\left| {\angle {{{\boldsymbol{A}}}} - \angle \widehat {{{\boldsymbol{A}}}}^\prime } \right|_\pi\) indicates the wrapped phase difference between the ground truth and the normalized all-optical transformation
