ABSTRACT
This chapter describes three experiments to test and demonstrate the principles of quantum mechanics using correlated photons. These include the demonstration that the photon exists; production and measurement of entangled states of photons, including a measurement of a violation of a Bell inequality; and the interference of a single photon with itself and the quantum eraser. The experiments are presented in order of difficulty. In a birefringent medium, spontaneous parametric down-conversion occurs due to the interaction of the light and the medium. The analysis given can be generalized to show that the down-converted photons are created in planes other than the horizontal plane. All the down-converted photons of a given wavelength form a cone about the pump-beam axis, but photons in each pair follow, by conservation of momentum, correlated paths in the cone. The down-converted photons are created in a cone about the pump-beam direction. The experiment uses the horizontal slice of the down-conversion cone that contains the pump beam.
