function [ax, co] = air(T)
% AIR return complex axial and coplanar field as a function of T

% T is the ratio of distance to transition distance, i.e. T = kr

ax = 2*(1 + i*T);
co = 1 + i*T -T.^2;

ax = 2 * sqrt(2) * ax .* exp(-i*T) ./ T.^3;
co = 2 * sqrt(2) * co .* exp(-i*T) ./ T.^3;

% the values are scaled so that the axial field has unity magnitude
% at T=1