Device and method for investigating one or a plurality of phase objects

A method for investigating one or a plurality of phase objects, the method comprising:

• illuminating, with light of a light source, a grid made up of rigid elements, wherein the coherence length of the light source is larger than the average spacing of adjacent rigid elements of the grid;
• generating a diffraction image of the illuminating light scattered on the grid;
• wherein the diffraction image is a Fraunhofer diffraction pattern comprising light maxima at which illuminating light positively interferes;
• placing the one or the plurality of phase objects in the light path between the light source and the grid and/or in the light path of the illuminating light scattered on the grid, wherein the grid generates a diffraction image upon illumination in absence of any phase objects, and wherein the phase objects placed between the light source and the grid and/or in the light path of the illuminating light scattered on the grid change the diffraction image of the grid;
• detecting at least a part of the diffraction image by an optical sensor directly or after interaction with further optical components;
• converting using an optical detector the detected diffraction image or the detected part of the diffraction image into a signal;
• and
• analyzing the signal to ascertain information relating to the one or plurality of phase objects therefrom.