finesse.model.Model.phase_config

Model.phase_config(zero_k00=False, zero_tem00_gouy=True)[source]

Coupling coefficient and Gouy phase scaling:

  • phase_level 3 == zero_k00=True, zero_tem00_gouy=True

  • phase_level 2 == zero_k00=False, zero_tem00_gouy=True

  • phase_level 1 == zero_k00=True, zero_tem00_gouy=False

  • phase_level 0 == zero_k00=False, zero_tem00_gouy=False

See also Phase configuration settings

This can be used to change the computation of light field phases in the Hermite-Gauss mode. In general, in the presence of higher order modes, the “macroscopic length” of a space is no longer an integer number of wavelengths for the TEM00 mode because of the Gouy phase. Furthermore, the coupling coefficients \(k_{nmnm}\) contribute to the phase when there is a mode mismatch. For correct analysis these effects have to be taken into account. On the other hand, these extra phase offsets make it very difficult to set a resonance condition or operating point intuitively. In most cases another phase offset can be added to all modes so that the phase of the TEM00 becomes zero.

This method allows setting these phase offsets for the propagation through free space, for the coupling coefficients, or both. Regardless of the setting, the phases for all higher modes are changed accordingly such that the relative phases remain correct.

Parameters
zero_k00bool, optional

Scale phase for k0000 (TEM00 to TEM00) coupling coefficients to 0. Defaults to True.

zero_tem00_gouybool, optional

Ensure that all Gouy phases for TEM00 are 0. Defaults to True.