Iterative correction process for optical thin film synthesis with the Fourier transform method

Several errors inherent to the Fourier transform method for optical thin film synthesis, including the inaccuracy of the spectral functions Q (sigma) used in the Fourier transforms, are compensated numerically by using successive approximations. We show that the complex phase of Q (sigma) is a key parameter which can be exploited to reduce significantly the thickness of the synthesized films and to control the shape of the refractive index profiles without affecting the spectral performance. This method is compared to other well established thin film design techniques.