| 摘要 |
A method measures the three dimensional position of particles in a fluid medium contained in a sample by recording a digital hologram of the particles on an image sensor and by reconstructing the image of the particles from the hologram. The recording includes providing a source beam with a coherent source, and generating at least two beams from the source beam, namely a reference beam and at least one object beam, wherein the reference beam and the object beam are mutually coherent. The sample is illuminated by condensing the object beam onto the sample in order to obtain a scattered object beam for each particle. The scattered object beam is scattered into a spherical converging object beam toward the image sensor for each particle. Further, the recording includes forming a diverging spherical beam from the reference beam, and superposing the spherical converging object beam for each particle and the diverging spherical beam on the image sensor in order to obtain on the image sensor an hologram of the particles by interfering the beams.
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