Demonstration of Quantum Polarization Microscopy using an Entangled-Photon Source

TL;DR

This paper demonstrates a quantum polarization microscopy technique using entangled photons, offering a novel imaging contrast method based on photon coincidence counts, which could surpass classical microscopy in resolution and contrast.

Contribution

The study introduces an experimental quantum polarization microscopy method utilizing entangled-photon sources, with a new contrast mechanism based on photon coincidence statistics.

Findings

Coincidence counts produce a thermal-like photon state with high autocorrelation peak.

Single-photon coincidence counts result in a dispersive thermal state with lower autocorrelation peak.

Switching between states is achieved by adjusting the polarization analyzer angle.

Abstract

With the advancement of non-classical light sources such as single-photon and entangled-photon sources, innovative microscopy based on the quantum principles has been proposed over traditional microscopy. This paper introduces the experimental demonstration of a quantum polarization microscopic technique that incorporates a quantum-entangled photon source. Although the point that employs the variation of polarization angle due to reflection or transmission at the sample is similar to classical polarization microscopy, the method for constructing image contrast is significantly different. Image contrast is constructed by the coincidence count of signal and idler photons. In the case that coincidence count is recorded from both the signal and idler photons, the photon statistics resemble a thermal state, similar to the blackbody radiation, but with a significantly higher peak intensity in the second order autocorrelation function at zero delay that is derived from coincidence count. While, when the coincidence count is taken from either the signal or idler photon only, though the photon state exhibits a thermal state again, the photon statistics become more dispersive and result in a lower peak intensity of the autocorrelation function. These different thermal states can be switched by slightly changing the photon polarization, which is suddenly aroused within narrow range of analyzer angle. This polarization microscopic technique can provide a superior imaging technique compared to the classical method, opening a new frontier for research in material sciences, biology, and other fields requiring high-resolution imaging.