finesse.gaussian.BeamParam.S¶

property BeamParam.S¶

Defocus (wavefront curvature), \(S\), of the Gaussian beam, equivalent to the reciprocal of BeamParam.Rc.

Computed as,

\[S = \frac{z}{z^2 + z_R^2},\]

where \(z\) is the distance to the waist position (given by BeamParam.z, or BeamParam.real) and \(z_R\) is the Rayleigh range (given by BeamParam.zr, or BeamParam.imag).

Hint

Use BeamParam.curvature() to compute the curvature as a function of any of the above dependent arguments.