Function radiation_pattern

python/examples/disc_radiation_pattern.py:99–134

Computes the radiation pattern from the far fields. Args: sim: a `Simulation` object. n2f_mon: a `DftNear2Far` object returned by `Simulation.add_near2far`. Returns: Array of radial Poynting flux, one for each point on the circumference of a quarter circle w

(sim: mp.Simulation, n2f_mon: mp.DftNear2Far)

def radiation_pattern(sim: mp.Simulation, n2f_mon: mp.DftNear2Far) -> np.ndarray:
    """Computes the radiation pattern from the far fields.

    Args:
        sim: a `Simulation` object.
        n2f_mon: a `DftNear2Far` object returned by `Simulation.add_near2far`.

    Returns:
        Array of radial Poynting flux, one for each point on the circumference of
        a quarter circle with angular range of [0, π/2] rad. 0 rad is the +z
        direction and π/2 is +r.
    """
    e_field = np.zeros((NUM_POLAR, 3), dtype=np.complex128)
    h_field = np.zeros((NUM_POLAR, 3), dtype=np.complex128)
    for i in range(NUM_POLAR):
        far_field = sim.get_farfield(
            n2f_mon,
            mp.Vector3(
                FARFIELD_RADIUS_UM * math.sin(polar_rad[i]),
                0,
                FARFIELD_RADIUS_UM * math.cos(polar_rad[i]),
            ),
            GREENCYL_TOL,
        )
        e_field[i, :] = [far_field[j] for j in range(3)]
        h_field[i, :] = [far_field[j + 3] for j in range(3)]

    flux_x = np.real(
        np.conj(e_field[:, 1]) * h_field[:, 2] - np.conj(e_field[:, 2]) * h_field[:, 1]
    )
    flux_z = np.real(
        np.conj(e_field[:, 0]) * h_field[:, 1] - np.conj(e_field[:, 1]) * h_field[:, 0]
    )
    flux_r = np.sqrt(np.square(flux_x) + np.square(flux_z))

    return flux_r


def disc_radiated_flux(disc_um: float, source_zpos: float) -> Tuple[float, float]: