Retrieving the refractive index prole of a holographic grating by diffraction experiments

摘要

It is well known that in standard diffaction experiments only the amplitudes of structural Fourier componentsare recovered but phase information is lost. This problem is known as the 'phase problem' in crystallography. Inthis contribution, we point out how the phase problem of diffraction can be solved in some particular cases byemploying multi-wave interference. In the experimental situation described here, we were able to determine theform of the refractive-index profile of a 1-D nanocomposite holographic grating by using a multi-wave couplinganalysis of the measured angular dependence of the diffraction efficiencies for a number of diffgraction orders.