Revealing photons behaviors in a birefringent interferometer

TL;DR

This paper investigates photon behaviors in a birefringent interferometer, revealing two-photon super-resolution effects, thermal dispersion coefficients, and polarization-dependent decoherence, advancing quantum-enhanced optical metrology.

Contribution

It provides a comprehensive study of photon interference in birefringent interferometers, including two-photon beatings and super-resolution, which was not previously explored.

Findings

Two-photon interference fringes beat twice as fast as single-photon fringes.

Thermal dispersion coefficients can be determined from a single measurement.

Photon bandwidth influences beating behaviors through polarization-dependent decoherence.

Abstract

The interferometer is one of the most important devices for revealing the nature of light and for precision optical metrology. Though lots of experiments were performed for probing photons behaviors in various configurations, a complete study of photons behavior in a birefringent interferometer has not ever been performed. Based on an environmental turbulence immune Mach-Zehnder interferometer, tunable photonic beatings by rotating a birefringent crystal versus the temperature of the crystal for both single-photon and two-photon are observed. Furthermore, the two-photon interference fringes beat two times faster than the single-photon interference fringes. This beating effect is used to determine the thermal dispersion coefficients of the two principal refractive axes with a single measurement, the two-photon interference shows super-resolution and high sensitivity. Obvious differences between two-photon and single photon interference are also revealed in an unbalanced situations. In addition, influences of the photon bandwidth to the beating behaviors that come from polarization-dependent decoherence are also investigated. Our findings will be important for better understanding the behavior of two-photon interference in a birefringent interferometer and for precision optical metrology with quantum enhancement.