Interference between a Two-Photon State and~a Coherent State

A. Windhager, M. Suda, Christoph Pacher +2 more

Tingyu Li, Saburo Sakurai, Katsuyuki Kasai +3 more

We experimentally demonstrated a three-photon interference on a beam splitter between a weak coherent state and a two-photon state produced by a spontaneous parametric down conversion. It indicates that a combined three-photon probability amplitude, which is formed by the two-photon state and one-photon from the coherent state, can be used to interfere with another three-photon probability amplitude from the coherent state. The observed three-photon coincidence rate showed that the interference depended on not only the relative phase between the two interference field but also the amplitude of the weak coherent state. This may introduce another free parameter for preparing quantum state, such as high N00N state, with quantum interference.

Yun Zhang, Lirong Wang, Masayoshi Watanabe

Multi-photon interference between a two-photon state and a weak coherent state is presented. The results show that the interference depended on not only the relative phase but also the amplitude between the two interference fields.

Jianbin Liu, Yu Zhou, Huaibin Zheng +3 more

Aojie Xu, Lifeng Duan, Lirong Wang +1 more

We experimentally investigate two-photon interference between a weak coherent state and a heralded single-photon state, producing from a spontaneous parametric down conversion. Both the unequal spectrum linewidth and average photon number ratio in a given time interval are considered in our model. We obtained excellent agreement between our experimental data and prediction from our model. Furthermore, the range of observing high visibility two-photon interference is significantly extended by isolating coincidence events from two-photon contributions in the weak coherent state. These results may throw some new light on quantum information technology when the two-photon interference with independent sources is required.

Paul G. Kwiat