Photon Correlations and interference in type-1 optical parametric down-conversion

Yanhua H. Shih, Alexander V. Sergienko

Roger Andrews, Andrea T. Joseph, Edward R. Pike +1 more

Thomas E. Kiess

Chung Ki Hong

Roger Andrews, Edward R. Pike, Sarben Sarkar

In this work we develop a quantum theory for fourth-order interference effects of non-degenerate (ND) and degenerate (D) photons produced in type-I spontaneous parametric down-conversion. In the first part of this work we include the effect of crystal dispersion whereby we obtain distinct amplitudes for ND and D photons. In the second part, the effects produced by changes in crystal length and beam-waist radius on photon-pair correlations and fourth-order interference were examined. The effect of such changes on ND and D photons was found to be different and therefore we conclude that ND and D photons are inherently distinguishable quantum states of the photon field.

Minhaeng Cho

Parametric down-conversion is a second-order nonlinear optical process annihilating a pump photon and creating a pair of photons in the signal and idler modes. Then, by using two parametric down-converters and introducing a path indistinguishability for the two generated idler modes, a quantum coherence between two conjugate signal beams can be induced. Such a double spontaneous or stimulated parametric down-conversion scheme has been used to demonstrate quantum spectroscopy and imaging with undetected idler photons via measuring one-photon interference between their correlated signal beams. Recently, we considered another quantum optical measurement scheme utilizing W-type tripartite entangled signal photons that can be generated by employing three spontaneous parametric down-conversion crystals and by inducing coherences or path-indistinguishabilities between their correlated idler beams and between quantum vacuum fields. Here, we consider an extended triple stimulated parametric down-conversion scheme for quantum optical measurement of sample properties with undetected idler and photons. Noting the real effect of vacuum field indistinguishability on the fringe visibility as well as the role of zero-point field energy in the interferometry, we show that this scheme is an ideal and efficient way to create a coherent state of W-type entangled signal photons. We anticipate that this scheme would be of critical use in further developing quantum optical measurements in spectroscopy and microscopy with undetected photons.