Abstract
We fabricated our PPKTP crystal into a doubly-resonant cavity. By utilizing the nonlinear effect of the crystal, and the wide cluster spacing of the cavity, we hoped to construct a relatively simple setup for generation of biphoton source, which is suitable for application in the quantum information science, and furthermore estimated the qualities of our generated photons experimentally. We experimentally justified the biphotons’ narrow bandwidth and positive correlation; we then searched for the crystal temperature that generates biphotons to have interaction with rubidium atoms. We observed absorption of one of the biphotons by rubidium atoms at two different temperatures each when the pump beam was at two separate frequencies. According to this result and the tendency we found from our simulation model, we came up with a possible way to generate biphotons that can be simultaneously absorbed by rubidium atoms.