Function port_waves 

fn port_waves<const N: usize>(
    ks: [[Complex; 2]; 2],
    zs: [Complex; 2],
    q: [f64; 2],
    axis: usize,
    helicity: bool,
    fixed_q: bool,
) -> Result<[[[[Jet<N>; 4]; 2]; 2]; 2]>

The port fields of one diffraction group, as jets in the eight parameters when N = 8; parity bases combine the helicity fields.