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.

Getter:

Returns the defocus of the beam parameter. Read-only.