Recurrent fourth-order interference dips and peaks with a comblike two-photon entangled state

We demonstrate full selective control over the constructive or destructive character of fourth-order recurrent interferences in a modified version of a Hong-Ou-Mandel interferometer using comblike two-photon states. The comb spectral/temporal structure is obtained by inserting an etalon cavity in the signal path of an entangled photon pair obtained by pulsed spontaneous parametric down-conversion. Both a simple qualitative discussion and a complete theoretical derivation are used to explain and analyze the experimental data.