“…(
2018) and Palmeri et al. (
2022), Equation can be rewritten in an operator form, that is,
and, then, the Singular Value Decomposition (SVD) of
can be performed. Hence, denoting with
the resulting
‐th right‐hand singular function associated with the ℓ‐th order, each OAM spectrum mode can be expanded as follows (Palmeri et al.,
2022):
with
being suitable coefficients.…”