Fig. 1. Ellipsometry with (a), (b) correlated^[23] and (c) entangled photons^[63]: (a), (c) experiments and (b) overview of improved measurement accuracy.

Fig. 2. Experimental comparison of heralded and ghost polarimetry with polarization-entangled photon pairs^[30]: experiment (upper panel) and representative measurement outcome (lower panel).

Fig. 3. Advantage of the probing with NOON states^[9].

Fig. 4. Interferometric polarized light microscopy with NOON states^[32]: demonstration of increased phase sensitivity due to faster response function modulation (upper panel) and images under illumination with coherent light (a), NOON state N = 2 (b), NOON state N = 3 (c), and reference with bright illumination (d).

Fig. 5. Instrument for studying Bell state decoherence after interaction with brain tissue (upper panel) and Bell state metrics for healthy and Alzheimer’s disease affected tissues^[34].

Fig. 6. Concept of metasurface-assisted quantum ghost polarimetry for object classification^[57].

Fig. 7. Demonstration of differentiation of more than 80 samples with slightly different Mueller matrices, only with two coincidence measurements between the optical channels within the ghost measurement configuration^[26].

Fig. 8. Polarization-based sensing in ghost configuration using polarization-correlated photons and camera-based correlation measurements^[52].

Fig. 9. Experimental results of biological organisms imaging through spatial and polarization entanglement on the example of a zebrafish (adapted from Ref. [27]).