An analysis system comprises a transmitting device (1.1) and a receiving device (1.2). The transmitting devices comprises means for illuminating an object (1.3), or a part of the object, by a first light beam (1.8) consisting of signals with two distinct frequencies and first orthogonal polarisation states. The receiving device comprises means (1.6) for detecting, in a second light beam with second polarisation states and resulting from the illumination of the object to be analysed by the first light beam, a signal at a beat frequency equal to a difference between the two frequencies of the first light beam; and means (1.7) for obtaining information relating to the depolarising or dichroic character of the object, or of the part of the object, according to the detection or not of a signal at the beat frequency.