Depolarization sensing by field orthogonality breaking

This paper revisits the way of performing depolarization measurements using a novel concept of field orthogonality breaking, providing a direct characterization of the depolarization strength of a material from a single measurement. This technique, inspired by a microwave photonics approach, uses a superposition of two orthogonally polarized modes with a slight frequency detuning Δν to enlighten the sample. Using such illumination, it can be shown that the depolarizing strength of a sample can be directly retrieved from a single measurement of the beat note intensity, appearing at the frequency Δν. In other words, the depolarization strength of a given material can be recovered from the way this material breaks the orthogonality between two incident orthogonal states. In addition, it must be noted that this technique is well suited for endoscopic remote sensing, being inherently insensitive to fiber/endoscope birefringences which preserve polarimetric orthogonality.