Observations of super-resolution using phase-controlled coherent photons in a delayed-choice quantum eraser scheme

Super-resolution overcoming the standard quantum limit has been intensively studied for quantum sensing applications of precision target detection over the last decades. Not only higher-order entangled photons but also phase-controlled coherent photons have been used to demonstrate the super-resolution. Due to the extreme inefficiency of higher-order entangled photon-pair generation and ultralow signal-to-noise ratio, however, quantum sensing has been severely limited. Here, we report observations of coherently excited super-resolution using phase-controlled coherent photons in a delayed-choice quantum eraser scheme. Using phase manipulations of the quantum erasers, super-resolution has been observed for higher-order intensity correlations between them, satisfying the Heisenberg limit in phase resolution. This new type of precision phase-detection technique opens the door to practical applications of quantum sensing compatible with current technologies based on coherence optics.