Computes the (complex) fields from an Er point source at r=0 in vacuum.

freespace_cyl.py

import argparse
from numpy.linalg import norm
from numpy import conj
import meep as mp


def dipole_emission(res: float, dpml_r: float, dpml_z: float, s: float,
                    m: int, fcen: float) -> float:
    """Computes the complex fields from an Er point source at r=z=0 in vacuum."""

    cell_size = mp.Vector3(s+dpml_r,0,s+2*dpml_z)

    pml_layers = [
        mp.PML(dpml_r, direction=mp.R),
        mp.PML(dpml_z, direction=mp.Z),
    ]

    sources = [
        mp.Source(
            src=mp.GaussianSource(fcen,fwidth=0.1*abs(fcen),cutoff=10.0),
            center=mp.Vector3(),
            component=mp.Er,
        ),
    ]

    sim = mp.Simulation(
        resolution=res,
        cell_size=cell_size,
        dimensions=mp.CYLINDRICAL,
        m=m,
        sources=sources,
        boundary_layers=pml_layers,
    )

    # run for long enough for fields to enter PMLs
    # such that presence of PMLs has an effect on
    # the fields in the non-PML region
    sim.run(until=130.)

    er = sim.get_array(
        component=mp.Er,
        center=mp.Vector3(0.5*s,0,0),
        size=mp.Vector3(s,0,s),
        cmplx=True,
    )

    return er


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument(
        '-res',
        type=float,
        default=50.,
        help='resolution (default: 50.0)',
    )
    parser.add_argument(
        '-dpml_r',
	type=float,
	default=1.,
        help='PML thickness in r direction (default: 1.0)',
    )
    parser.add_argument(
	'-dpml_z',
        type=float,
	default=1.,
        help='PML thickness in z direction (default: 1.0)',
    )
    parser.add_argument(
        '-s',
        type=float,
        default=5.,
        help='thickess of non-PML region (default: 5.0)',
    )
    args = parser.parse_args()

    er1 = dipole_emission(args.res, args.dpml_r, args.dpml_z, args.s, -1, +1.)
    er2 = dipole_emission(args.res, args.dpml_r, args.dpml_z, args.s, -1, -1.)
    er3 = dipole_emission(args.res, args.dpml_r, args.dpml_z, args.s, +1, +1.)
    er4 = dipole_emission(args.res, args.dpml_r, args.dpml_z, args.s, +1, -1.)

    c = [ ['-1', '+1'], ['-1', '-1'], ['+1', '+1'], ['+1', '-1'] ]

    print(f"norm1:, {c[0]} {norm(er1):.2f}, {c[1]} {norm(er2):.2f}, "
          f"{norm(er1-conj(er2)):.2f}, {norm(er1-er2):.2f}")
    print(f"norm2:, {c[0]} {norm(er1):.2f}, {c[2]} {norm(er3):.2f}, "
          f"{norm(er1-conj(er3)):.2f}, {norm(er1-er3):.2f}")
    print(f"norm3:, {c[0]} {norm(er1):.2f}, {c[3]} {norm(er4):.2f}, "
          f"{norm(er1-conj(er4)):.2f}, {norm(er1-er4):.2f}")
    print(f"norm4:, {c[1]} {norm(er2):.2f}, {c[2]} {norm(er3):.2f}, "
          f"{norm(er2-conj(er3)):.2f}, {norm(er2-er3):.2f}")
    print(f"norm5:, {c[1]} {norm(er2):.2f}, {c[3]} {norm(er4):.2f}, "
          f"{norm(er2-conj(er4)):.2f}, {norm(er2-er4):.2f}")
    print(f"norm6:, {c[2]} {norm(er3):.2f}, {c[3]} {norm(er4):.2f}, "
          f"{norm(er3-conj(er4)):.2f}, {norm(er3-er4):.2f}")

output from running the script with default parameters:

norm1:, ['-1', '+1'] 0.30, ['-1', '-1'] 0.30, 0.00, 0.60
norm2:, ['-1', '+1'] 0.30, ['+1', '+1'] 0.30, 0.60, 0.00
norm3:, ['-1', '+1'] 0.30, ['+1', '-1'] 0.30, 0.00, 0.60
norm4:, ['-1', '-1'] 0.30, ['+1', '+1'] 0.30, 0.00, 0.60
norm5:, ['-1', '-1'] 0.30, ['+1', '-1'] 0.30, 0.60, 0.00
norm6:, ['+1', '+1'] 0.30, ['+1', '-1'] 0.30, 0.00, 0.60