Super-sensitive and visibility-enhanced imaging with NOON states for birefringent and isotropic samples

As an emerging microscopic detection tool, quantum microscopes based on the principle of quantum precision measurement have attracted widespread attention in recent years. Compared with the imaging of classical light, quantum-enhanced imaging can achieve ultra-high resolution, ultra-sensitive detection, and anti-interference imaging. Here, we introduce a quantum-enhanced scanning microscope under illumination of an entangled NOON state in polarization. For the phase imager with NOON states, we propose a simple four-basis projection method to replace the four-step phase-shifting method. We have achieved the phase imaging of micrometer-sized birefringent samples and biological cell specimens, with sensitivity close to the Heisenberg limit. The visibility of transmittance-based imaging shows a great enhancement for NOON states. Besides, we also demonstrate that the scanning imaging with NOON states enables the spatial resolution enhancement of √N compared with classical measurement. Our imaging method may provide some reference for the practical application of quantum imaging and is expected to promote the development of microscopic detection.