Phase retrieval from two intensity measurements in an optical system involving nonunitary transformation

Phase retrieval from measured intensities is achieved for a practical optical system involving nonunitary transformation. We use two specific light field distributions as an example to demonstrate the iterative algorithm for phase retrieval. We chose the initial phase value to have arbitrary random distribution. For a system with different diffraction losses, we find that the retrieval can be successfully achieved even though the measured intensities contain certain random fluctuations.