Investigation of Single Photon Purity from Raman Processes

Deterministic production of high purity photon states is essential for robust quantum communication and information applications. One way to implement the deterministic single photon production is the Duan-Lukin-Cirac-Zoller (DLCZ) protocol via phonon-mediated Raman processes. Although Raman processes have been well demonstrated, the purity of photons has remained largely unexplored. We investigate the effects experimental parameters have on the purity of single photons by using a phenomenological hamiltonian. We show how single photon purity depends on the length of the crystal and the bandwidth of the pump used to generate the photons. We compare our numerical simulations against experimental data showing qualitative agreement.