No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Optical Phase Information Due to the Vacuum in Two-Photon Down-Conversion
Abstract
According to QED single photons carry no phase information about the optical field, yet it is possible for a superposition of states, including the vacuum, to carry phase memory. We have demonstrated this principle by showing experimentally that the photon pairs generated in the process of parametric down-conversion,1 through their entanglement with the vacuum state, contain information about the phase of the pump field, as was recently pointed out by Grangier et al.2 However, our experimental technique is different from the one they proposed.
ResearchGate has not been able to resolve any citations for this publication.
It is shown that the two-photon phase coherence of parametrically generated photon pairs, which is at the origin of squeezed-light generation, can be directly probed using an intensity-correlation measurement. The resulting intensity correlation leads to a new violation of Bell's inequalities, which could be experimentally tested.
Simultaneity in optical photon pairs parametric production, verifying quantum mechanical description of fluorescence
A proposed experiment is analyzed theoretically. In the proposed experiment two coherent pump waves fall on two identical nonlinear crystals, down-converted signal and idler beams from the two crystals are mixed by two beam splitters, and the coincidence counting rate for photons leaving the beam splitters is measured. We show that this counting rate depends on the phase difference between the two coherent pump waves, and results from the interference of the vacuum with the down-converted photons. The experiment could be used to look for locality violations along the lines recently proposed by Grangier, Potasek, and Yurke [Phys. Rev. A 38, 3132 (1988)], but without the need for a coherent reference beam for homodyning.
An exposition is given of the fundamental ideas of the recently opened field of two-particle interferometry, which employs spatially separated, quantum mechanically entangled two-particle states. These ideas are illustrated by a realizable arrangement, in which four beams are selected from the output of a laser-pumped down-converting crystal, with two beams interferometrically combined at one locus and two at another. When phase shifters are placed in these beams, the coincident count rates at the two loci will oscillate as the phases are varied, but the single count rates will not.