Quantum erasure based on orbital angular momentum of photons

The quantum eraser effect exemplifies the distinctive properties of quantum mechanics that challenge classical intuition and reveal the wave-particle duality of light. Whether the photon exhibits particle-like or wave-like behavior depends on whether the path information is discernible. In this paper, we propose a novel quantum eraser scheme that utilizes photonic phase structures as the which-way indicator. This scheme is implemented using a Mach-Zehnder interferometer (MZI), where one arm is configured with orbital angular momentum (OAM) to establish predetermined which-way information. Consequently, at the output ports of the MZI, the photon displays particle-like characteristics when the which-way information is retained. However, the introduction of an additional spiral phase plate (SPP) to eliminate the phase structure from the output photon of the MZI unveils distinct interference patterns. This result enhances our understanding of the quantum erasure effect.