VRS kernel definition for Ez

Hello,

I am not sure if the definition of the Ez field for vectorial RS agrees with the expression in the paper http://dx.doi.org/10.1088/1612-2011/10/6/065004.

This is from Line 783 of vector_fields_XY.py:

        e0z.u = e0x.u * self.X / r + e0y.u * self.Y / r
        Ez = e0z.RS(z=z,
                    n=n,
                    new_field=True,
                    kind='0',
                    verbose=verbose,
                    amplification=amplification)

And here is the definition of the kernel when kind='0' from Line 2437 of scalar_fields_XY.py:

    elif kind == '0':
        return 1 / (2 * pi) * exp(1.j * k * R) / R * (1 / R - 1.j * k)

However, as you can see in the attached formula 2(c), it seems to me that the factors X/R and Y/R should be in the definition of the kernel and that there should be separate kernels convolved with Ex and Ey when calculating Ez. To be more specific, Ex should convolve with 1 / (2 * pi) * exp(1.j * k * R) * x / R**2 * (1 / R - 1.j * k) and Ey should convolve with 1 / (2 * pi) * exp(1.j * k * R) * y / R**2 * (1 / R - 1.j * k) possibly with a -1 sign as well (c.f. Eq (7-8) in https://opg.optica.org/ao/abstract.cfm?uri=ao-45-6-1102).

Thank you for making such a great library available.