Patent ID: 7362449

Claim:
A microscope able to work in digital holography for obtaining three dimensional (3D) images of a sample, said microscope comprising as elements at least: (i) illumination means for illuminating in transmission and/or in reflection a sample and producing thereby a sample beam, said illumination means being characterised by a given spectral width having a maximum illumination wavelength; (ii) imaging means comprising a microscope objective having a front focal plane, and focusing means having a back focal plane; (iii) an interferometer for generating interfering beams from the sample beam, said interferometer being located behind the microscope objective and in front of the focusing means, and comprising a first interferometer arm and a second interferometer arm, the focusing means having one front focal plane in each of said first and second interferometer arms, said first interferometer arm comprising a first beam splitter a first reflecting element and a second beam splitter, said second interferometer arm comprising the first beam splitter, a second reflecting element and the second beam splitter, wherein some of said reflecting elements and beam splitters are mounted on a moving means so as to equalise the optical length of the interfering beams with an accuracy in the range of less than the maximum wavelength of the illumination means to a few maximum wavelengths; (iv) an electronic imaging devices provided with a sensor which is located in the back focal plane of the focusing means, for detecting and recording the fringe interference images formed thereon by the interfering beams; (v) processing means conceived for at least processing said fringe interference images by digital holography techniques; wherein said microscope further comprises: (vi) a positioning stage located outside the interferometer in front of the microscope objective for positioning the sample substantially in the front focal plane of the microscope objective; (vii) tilting means located in the second interferometer arm, respectively in the first interferometer arm, for tilting the beam reflected by the second reflecting element, respectively first reflecting element, relatively to the beam reflected by the first reflecting element, respectively the second reflecting element, by a precise tilting angle in such a way to superpose the beam reflected by the first reflecting element, respectively the second reflecting element, and the beam reflected by the second reflecting element, respectively the first reflecting element, in a set of front focal planes of the focusing means thereby creating a precise shift between the interfering beams reflected and transmitted by the second beam splitter on the sensor of the electronic imaging device, wherein the set of front focal planes comprises a first front focal plane of the focusing means corresponding to the first interferometer arm and a second front focal plane of the focusing means corresponding to the second interferometer arm.