Determination of pitch in twisted cylinders by electromagnetic scattering

We consider the electromagnetic inverse medium scattering problem for a twisted uniaxial cylinder in a homogeneous background. Our objective is to determine the pitch for small values using scattered data originating from a plane wave incident orthogonal to the cylinder axis. The problem is transformed to the solution of two coupled ordinary differential equations that decouple by the Born approximation. Based on this solution, a number of potential measuring methods suitable for the inverse problem are presented and analysed. Particular attention is paid to the stability of the solution for the pitch to changes in the dielectric coefficients.