Patent ID: 7710573

Claim:
A device for noninvasive detection of the properties of a medium by interferometry, this device comprising: an optical source for illuminating at least one region of the medium to be probed, with a light beam whose path defines an optical axis; means for measuring variations in the phase of the light beam during its passage through the region to be probed, these measurement means comprising an interferometer for splitting the light beam into a reference beam and a probe beam, and means for servocontrolling the path lengths of the reference beam and of the probe beam, in this interferometer the the respective path lengths of the reference beam and of the probe beam being servocontrolled up to a cutoff frequency f c and having a signal sampling frequency f a , wherein said device further includes means for scanning, with the probe beam, the region to be probed and a reference region with an image acquisition frequency f for images recorded by the means for measuring the variations in the phase of the light beam above the cutoff frequency f c .