The Study Of The Interference Of Two-photon

The interference is one behavior of the coherence. Till now, people have known very well about the interferences of the mechanical and electromagnetic waves. But the interference in the quantum mechanics world has not yet been utterly understood. And the interference of two-photon, one type of the optical field's second-order interference, has many unknown secrets. As to the interference of photons, Dirac had given a famous remark,"each photon interferes only with itself and interference between different photons never occurs". So the interference of the two-photon has been considered as an impossible phenomenon for a long time. At the present time the bone of contention is the explanation of the interference of two-photon. One viewpoint is about that the superposition of the two photon's wave functions introduces the interference of two-photon, while another viewpoint says that the interference can take place because the wave functions of two-photon states can't be distinguished. In this paper we hold out the last viewpoint, and we think that the interference of two-photon reflects the coherence of the two-photon possible states which can't be distinguished in principle. A scheme which will be able to discriminate the two photons from each other while the two photon states are indistinguishable will be put forward in this paper.The content of this paper is listed as follows.In the first chapter the basic theories are introduced.In the second chapter, we will introduce the basic apparatuses and measure method with the interference of two-photon.In chapter three, we will introduce the three famous types of the two-photon interference: Hong-Ou-Mandel type, Franson type and the same way type, and give out the interpretation of the three types interference. Then the scheme will be put forward in this chapter. In this two-photon interference scheme the polarized directions of the two photons are vertical, but the distinguishable information of polarization will not be erased. At the end of this chapter is the comprehension about the two-photon interference.In the last chapter we will discuss the general HOM interference and give another interpretation of the result.