Method for imaging and/or spectroscopy using an interferometer setup, comprising the steps i) generation of a first signal field s 1 and a first idler field i 1, by pumping a first non-linear medium with a pump beam, such that the two fields are correlated, ii) illumination of an object with the first idler i 1 field, respectively by transmission and/or reflection, iii) generation of a second signal field s 2 and a second idler field i 2, - by pumping a spatial separate second non-linear medium with the pump beam, or - by pumping the first non-linear medium a second time with the pump beam, such that the two fields are correlated, iv) combination of the first i 1 and second i 2 idler fields (12, 22), such that the two fields are indistinguishable, and combination of the first s 1 and second s 2 signal fields (11, 21), such that the two fields interfere, v) first measurement of the interfered signal field s 12 by a detection means, vi) one or more additional measurements of the interfered signal field s 12 by the detection means, wherein for each additional measurement in step vi) a phase shift α is generated in the setup, and the phase shift is varied in a known manner at each of the one or more additional measurements, and wherein the first measurement in step v) and the one or more additional measurements in step vi) are all carried out within a stability time of the interferometer setup, and vii) calculation of a phase function Φ of the object out of the measurements from step v) and step vi) in order to get an image and/or a spectrum of the object. i) generation of a first signal field s 1 and a first idler field i 1, by pumping a first non-linear medium with a pump beam, such that the two fields are correlated, ii) illumination of an object with the first idler i 1 field, respectively by transmission and/or reflection, iii) generation of a second signal field s 2 and a second idler field i 2, - by pumping a spatial separate second non-linear medium with the pump beam, or - by pumping the first non-linear medium a second time with the pump beam, such that the two fields are correlated, - by pumping a spatial separate second non-linear medium with the pump beam, or - by pumping the first non-linear medium a second time with the pump beam, such that the two fields are correlated, iv) combination of the first i 1 and second i 2 idler fields (12, 22), such that the two fields are indistinguishable, and combination of the first s 1 and second s 2 signal fields (11, 21), such that the two fields interfere, v) first measurement of the interfered signal field s 12 by a detection means, vi) one or more additional measurements of the interfered signal field s 12 by the detection means, wherein for each additional measurement in step vi) a phase shift α is generated in the setup, and the phase shift is varied in a known manner at each of the one or more additional measurements, and wherein the first measurement in step v) and the one or more additional measurements in step vi) are all carried out within a stability time of the interferometer setup, and wherein for each additional measurement in step vi) a phase shift α is generated in the setup, and the phase shift is varied in a known manner at each of the one or more additional measurements, and wherein the first measurement in step v) and the one or more additional measurements in step vi) are all carried out within a stability time of the interferometer setup, and vii) calculation of a phase function Φ of the object out of the measurements from step v) and step vi) in order to get an image and/or a spectrum of the object.