finesse.solutions.beamtrace.BeamTraceSolution.q

BeamTraceSolution.q(node)

A convenience method for getting the non-astigmatic beam parameter at a node.

Warning

This is only intended to be used on nodes which do not exhibit astigmatism. If qx != qy at the node then this method will raise a ValueError.

To get both qx and qy at a node use either:

qx, qy = trace[node]

or:

qx, qy = trace.get(node)

where trace is an instance of this class.

Parameters:

nodeOpticalNode

The node at which to obtain q.

Returns:

qBeamParam

The beam parameter (which is the same in both planes) at the node.

Raises:

exValueError

If the beam parameters qx != qy at the node.