Tracing the beam

In general the Gaussian beam parameter of a \(\M{00}\) mode is changed at every optical surface (see Transformation of the beam parameter). In other words, for each location inside the interferometer where field amplitudes are to be computed a certain beam parameter has to be set for the simulation.

A possible method to find reasonable beam parameters for every location in the interferometer (every node in Finesse) is to first set only some specific beam parameters and then derive the remaining beam parameters from these initial ones: usually it is sensible to assume that the beam at the input can be properly described by the (hopefully known) beam parameter of the laser’s output mode. In addition, in most cavities the light fields can be described safely by using cavity eigenmodes.

Algorithm details


Rewrite this section now that beam tracing is done very differently to when this section was originally written. This should contain details, with examples, of how the binary tree structure and related algorithms work.