METHOD AND DEVICE FOR CHARACTERISING A COHERENT LIGHT FIELD IN AMPLITUDE AND PHASE

摘要

The invention relates to a method and a device for characterising a coherent light field (1) in amplitude and phase, the method having the following steps: • providing an object (10) with known transmission function T(x,y) for the light field (1) in amplitude and phase; • irradiating the object (10) with the coherent light field (1) to be characterised in an object plane (11) in which the object (10) is arranged; • detecting an intensity distribution l'(x,y) of the diffraction image (22) of the light field (1) spatially behind the irradiated object (10) in a detector plane (21) by means of a flat detector (20); • reconstructing the light wave function u(x,y) after passage of same through the object (10) by iterative determination of phase and amplitude of the light wave from the intensity distribution l'(x,y) detected; • calculating the light wave (1) before passage through the object by applying the known transmission function T(x,y) to the reconstructed light wave function u(x,y). According to the invention, an object with a structure region (12) is used as the object (10), the structure region (12) of the object (10) being defined by a transmission mask which provides for only strong absorbing regions (13) with a transmission T ≈ 0 and non-absorbing regions (14) with a transmission of T ≈ 1.