Imaging birefringent patterns using radial polarizations of entangled biphotons

We introduce a quantum imaging microscopy technique using radial polarization imaging with entangled idler/signal photons to measure birefringent micropatterns. Using a radial wave plate that converts linear polarizations to radial, the signal photons in radial polarization states are imaged at an intensified single-photon camera triggered by the idler photons that have interacted with the birefringent material of the pattern. From the single-frame coincidence images, the local birefringence properties are extracted, enabling phase mapping over the pattern. Our imaging technique may open new avenues for real-time remote measurements of dynamic birefringence.