grasp2alm.BeamGauss.get_alm

BeamGauss.get_alm(lmax: int, mmax: int, ellipticity: float | None = 1.0, psi_ell_rad: float | None = 0.0, psi_pol_rad: float | None = 0.0, cross_polar_leakage: float | None = 0.0) → ndarray

Return an array of spherical harmonics \(a_{\ell m}\) that represents a Gaussian beam

Parameters:

• lmax (int) – The maximum value for \(\ell\)

• mmax (int) – The maximum range for \(m\); usually this is equal to lmax

• ellipticity (float) – The ellipticity of the beam, defined as major axis/minor

• 1 (axis. Default is)

• psi_ell_rad (float) – The inclination of the major axis of the ellipse with

• 0. (respect to the x-axis. This is not relevant for cirular beams. Default is)

• psi_pol_rad (float) – The polarization of the beam with respect to the x-axis,

• rad. (if None only I beam will be returned. Default is 0)

• cross_polar_leakage (float) – The cross-polar leakage (pure number). Default is 0.

Returns:

\(a_{\ell m}\) values (numpy.ndarray)