Optimization of interferometric generation of radially polarized laser beam

In this paper, we consider a technique which is both diffractive and interferometric for converting a linearly polarized TEM laser beam into a radially polarized beam with uniform azimuthal intensity distribution. The basic idea is to achieve the coherent summation of two orthogonally polarized Hermite-Gaussian TEM and TEM beams by using a vectorial Mach-Zehnder interferometer. The beam transformation TEM₀₀→TEM₁₀ and TEM₀₀→TEM₀₁ is achieved in each interferometer arm by using a simple diffractive optical element which is referred as a phase step which is made of a transparent glass on which a thin polymer film is deposited.