A study on the improvements and limitations of image quality in quantum polarization microscopy using an entangled-photon source

Quantum imaging is an advanced method for microscopy and investigating the optical properties of materials or biomedical samples with high accuracy, low noise, and minimal photo-damage. Previously, we proposed a quantum imaging technique where variations in polarization angle due to reflection or transmission enhanced image contrast in the second-order autocorrelation function at zero delay, g²(0). However, the observed image resolution was insufficient. In this study, we optimized the coincidence window to better distinguish photon statistics and used an objective lens to focus the entangled photon beams, improving image quality. Although effective for various samples, this method has limitations for samples exhibiting polarization disturbances such as photon scattering. Nevertheless, it demonstrates superior imaging performance under noisy conditions and low illumination, offering potential for high-quality quantum imaging applications.