A device for phase microscopy is disclosed that comprises a spatial light modulator and a connecting means adapted to fix the spatial light modulator onto a phase microscope. The phase microscope comprises a light path comprising at least a sample area, a light device for lighting said sample area, and an imaging device for capturing a phase image of said sample area. The phase image is a 2D matrix of pixels. The spatial light modulator is positioned in the light path in a conjugated plane of the sample area. The device also comprises a command of the spatial light modulator connected to the imaging device and adapted to measure the phase shift of a plurality of pixels of the phase image and to command the spatial light modulator in order to subtract the measured phase shifts.