ENTANGLED QUANTUM STATES IN CONSECUTIVE AND CASCADE NONLINEAR OPTICAL PROCESSES

摘要

Two schemes for producing entangled photon states with different frequencies are considered, with one frequency being smaller than the pumping frequency and the other one higher than the pumping frequency. It is shown that such frequency-entangled states can be obtained at consecutive interactions in a single periodically poled nonlinear crystal or in cascade processes that are realized in two crystals located one after the other. A comparison of the efficiencies for producing the frequency-entangled states in such methods is done. It is shown that the consecutive interaction is more effective than the cascade one for producing entangled quantum states and squeezed light.