AN EFFICIENT METHOD FOR GENERATING QUANTUM ENTANGLED PHOTON PAIRS

Abstract

Quantum entanglement plays a crucial role in quantum information science, particularly in quantum teleportation and the development of quantum key distribution (QKD). It is a phenomenon in which the quantum state of each particle in a pair or a group of particles is correlated to others and cannot be described independently. In this study, we demonstrate a simplified experimental setup for generating entangled photon pairs using spontaneous parametric down-conversion (SPDC) in a beta barium borate (BBO) crystal. A paper mask, designed to fit a down-converted photon path, crucially simplifies the alignment of optical components, leading to a significant improvement in the placement of detectors. The state of the generated entangled photons is then measured by two detectors equipped with polarization filters, to examine the correlation of the entangled photons. The coincidence counts were measured while varying the rotation angles of the polarizers. The first polarizer was oriented at 0°, 45°, 90°, and 135° relative to the vertical axis, while the second polarizer was rotated in 15° increments starting from 0°. The Bell-CHSH inequality test was performed, yielding an S = 2.709 ± 0.083, indicating strong quantum entanglement. This practical approach for generating entangled photon pairs offers simplicity while achieving strong entanglement, which is essential for quantum communication applications.