METHOD OF PREPARING ENTANGLED STATES OF SINGLE-PHOTON FIELD AND QUANTUM MEMORY FOR QUANTUM REPEATERS Russian patent published in 2024 - IPC G02F3/00 G02F1/35 H04B10/70 H04B10/291 

FIELD: optics.

SUBSTANCE: invention relates to nonlinear and quantum optics and specifically to a method of generating two-photon states and recording one of the photons in quantum memory to increase efficiency of quantum repeaters. Method of preparing entangled states of a single-photon field and quantum memory for quantum repeaters involves exposing a nonlinear medium in a resonator in which a nonlinear medium source is simultaneously placed and quantum memory, a pumping pulse, at which a phenomenon of spontaneous parametric scattering of light is observed with emission of a dummy photon at the wavelength of the fiber-optic communication channel and a signal photon at the wavelength of the resonator mode; recording the signal photon into the quantum memory by exposing the atomic ensemble in the resonator to the reference field pulse; reproduction of the signal field in the resonator by means of the action of the reading control field on the atomic ensemble in the resonator. Resonator mirrors have a high reflection coefficient only at the wavelength of the signal field, and for the idle field and the pumping field are transparent, one of the resonator mirrors is blind, and the other is output.

EFFECT: invention provides higher efficiency of recording.

1 cl, 1 dwg