Patent ID: 8665436

Claim:
A device for determining at least one piece of polarisation information for a measurement point of a target sample, said device comprising: a light source configured to emit a rectilinearly polarised light beam in a predefined direction, the light beam being intended to be reflected by the measurement point of the target sample, a calculation unit configured to calculate the polarisation information for the measurement point from the beam reflected by the target sample, at least one waveguide configured to guide the incident beam towards the target sample and the reflected beam towards the calculation means, said waveguide being a polarisation-maintaining optical fiber having a main optical axis parallel to the predefined direction, wherein the device additionally comprises a half-wave plate configured to rotate two orthogonal polarimetric components E ∥ I , E ⊥ I of the incident beam after passage through the waveguide, and two orthogonal polarimetric components E ∥ R , E ⊥ R of the reflected beam before passage through the waveguide, the polarimetric component E ⊥ I of the incident beam perpendicular to the predefined direction being zero, and wherein the half wave plate comprises at least one main optical axis which is orientable around an axis of rotation, said axis of rotation being perpendicular to the main optical axis and the predefined direction; the calculation unit being configured to calculate a piece of polarisation information based on the reflected beam measured from only three different orientations of the main optical axis of the half wave plate; said polarisation information being the orientation of the main axes and the phase shift induced by the birefringence of the target sample.