Experimental implementation of a quantum Differential Interference Constrast (DIC) microscope

We demonstrate experimentally a quantum version of Differential Interference Contrast (DIC) microscopy that makes use of the Hong-Ou-Mandel effect for phase retrieval. Contrary to other methods that use the HOM effect for imaging, our scheme does not require either the use of a reference photon with a well characterized spatial shape, neither numerical processing of the signal measured. The method can generate images of samples with subwavelength thickness, and these images can be obtained from experimental data in a straightforward manner.