Generation and characterization of entangled photons source through spontaneous parametric down conversion

Abstract

This thesis explores the generation and characterization of entangled photons source using a type-1 crossed Beta-Barium Borate (BBO) crystal through the spontaneous parametric down conversion (SPDC), with a focus on understanding the quantum entanglement phenomenon and its application in quantum information and communication. Various experimental tests, including Hanbury Brown and Twiss (HBT) experiment, visibility, Clauser-Horne-Shimony- Holt (CHSH) inequality, and polarization correlation measurements, were conducted to characterize the entangled photons source. Additionally, the quantum state tomography technique was used to reconstruct the density matrix of the entangled photons. The results show that the source generates moderately entangled, single photons, which violate the Bell inequality as evidenced by the CHSH parameter of 2.629±0.021. The concurrence value of 0.708 and linear entropy of 0.244 provide estimates of the degree of entanglement and noise present in the entangled photons, respectively.