NumericalAperture¶

Type:	float
Range:	[0, inf]
Default:	-/-
Appearance:	optional
Excludes:	Cartesian, Polar

Use the numerical aperture $\mathrm{NA}$ to define the range of the computed far field spectrum. When not set the entire propagating spectrum is computed.

With the notation of the FourierTransform section, far field directions $\pvec{k}$ with

$\begin{eqnarray*} \Re \left(\frac{\pvec{k}_\perp}{k_0} \right) \leq \mathrm{NA} \end{eqnarray*}$

are computed.