1,720,976 research outputs found
Two-photon entanglement generation: different Bell states within the linewidth of phase-matching
No full textTailoring polarization entanglement in anisotropy-compensated spontaneous parametric down-conversion
No full textSpectral properties of three-photon entangled states generated via three-photon parametric down-conversion in a chi((3)) medium
No full textWe consider the quantum state of light produced via direct parametric decay of pump photons into photon triples in a medium with cubic nonlinearity. For this state generated in the near-collinear frequency-degenerate regime, the third- and second-order Glauber's correlation functions are calculated and the intensity distribution over frequency and wave vector is found. It is shown that the number of photons generated into a single mode via the three-photon down-conversion is proportional to the width of the frequency-angular intensity distribution for the corresponding two-photon phase matching (spontaneous parametric down-conversion). The intensity of three-photon parametric down-conversion is shown to have an extremely broad frequency spectrum, even for a fixed angle of scattering
One- and two-photon interference from two temporally separated laser pulses
No full textAccording to Feynman, quantum mechanics teaches us that interference occurs when the relevant amplitudes become indistinguishable. In the case of first-order and second-order interference (order by "intensity"), the relevant amplitudes are one-photon and two-photon amplitudes, respectively. We report a quantum interference experiment in which the relevant amplitudes are associated with temporally well separated laser pulses. Both first- and second-order interference are observed under certain different conditions. The experimental setup is shown where a BBO crystal is pumped by two short UV laser pulses
Conditional unitary transformation on biphotons
No full textA conditional unitary transformation (90degrees polarization rotation) is performed at single-photon level. The transformation is realized by rotating polarization for one of the photons of a polarization-entangled biphoton state (signal photon) by means of a Pockel cell triggered by the detection of the other (idler) photon after polarization selection. As a result, the state of the signal photon is losslessly changed from being completely unpolarized to being partially polarized, so that the final polarization degree is given by the idler detector quantum efficiency. This experiment can be used for developing a different method of absolute quantum efficiency calibration
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