Observations of the nonclassical feature of photon bunching on a beam splitter using coherent photons along the same input port

TL;DR

This paper experimentally demonstrates nonclassical photon bunching on a beam splitter using coherent photons from the same input port, revealing quantum features of indistinguishability and wave nature.

Contribution

It presents the first experimental observation of photon bunching with coherent photons originating from the same input port, expanding understanding of quantum interference.

Findings

Photon bunching observed at 50% rate with same-input coherent photons

Nonclassical quantum feature demonstrated without two separate sources

Highlights the wave nature and indistinguishability in quantum optics

Abstract

One of the most striking quantum phenomena is photon bunching resulting from coincidently impinging two-indistinguishable photons on a beam splitter (BS) from two different input ports. Such a nonclassical feature has also been observed even between two independent light sources through either coherence optics resulting in phase locking or post-selected measurements such as quantum beating-based gating. Recently, BS physics regarding quantum features has been discussed using pure coherence optics based on phase basis superposition of the BS. Here, we experimentally demonstrate coherent photon bunching on a BS, where coherent photons come from the same input port. Although the mean values of both output photons are uniform and equal to each other, the mean value of the coincidence measurements between two output photons results in the nonclassical feature of photon bunching at a 50% rate. For this unprecedented result, we discuss the origin of indistinguishability for this quantum feature using the wave nature of a photon to understand the role of a BS in quantum mechanics.