Interferômetro de Hong-ou-Mandel com um e dois pares de fótons

Abstract

In the nonlinear optical process of spontaneous parametric down conversion, a laser beam incident in a nonlinear crystal, generates pairs of photons. In this process energy and momentum are conserved. This process is used in diverse studies in Quantum Optics. We worked with state of the parametric down-conversion process where two and four photons are generated. This state is used in the Hong-Ou-Mandel interferometer (HOM). The use of the HOM interferometer for studies with two entangled photons is vast. An intriguing phenomenon, observed in this and many other interferometer that uses optic pumping, is the reduction of the visibility of the tax of coincidence of photons, in the exit of the interferometer, with the increase of the power of the laser pump. In this work we study the dependence of the visibility of the standard of interference of fourth order with the power of the laser that generates the pairs of photons. Our results are in good agreement with experimental results.