Quantum confocal imaging based on entangled photons

Laser confocal imaging technology has become an important analytical tool in biological, biomedical, and materials science research, offering high imaging precision. However, this technology still has some limitations, especially in imaging biological samples (such as living tissues or cells), where the high intensity of the laser may cause irreversible photodamage. It has been proposed that quantum entangled light sources, instead of laser, can be used to avoid this drawback. In this paper, we experimentally demonstrated a quantum confocal imaging technology employing entangled photon sources with high brightness and stability. In the experiment, we obtained the point-by-point scanning imaging of a targeted area, in which a resolution of 3.91 <i>µ</i>m is achieved and the signal-to-noise ratio (SNR) degradation is suppressed. We also theoretically analyzed the potential of quantum confocal imaging to improve SNR performance in photodamage-free imaging. Our results could widen the application fields of confocal imaging technology and pave the way for applying the quantum technology in biological imaging.