Experimental generation of 84 dB entangled state with an optical cavity involving a wedged type-II nonlinear crystal

Abstract

Abstract:Entangled state of light is one of the essential quantum resources in quantum information science and technology. Especially, when the fundamental principle experiments have been achieved in labs and the applications of continuous variable quantum information in the real world are considered, it is crucial to design and construct the generation devices of entangled states with high entanglement and compact configuration. We have designed and built an efficient and compact light source of entangled state, which is a non-degenerate optical parametric amplifier (NOPA) with the triple resonance of the pump and two subharmonic modes. A wedged type-II KTP crystal inside the NOPA is used for implementing frequency-down-conversion of the pump field to generate the optical entangled state and achieving the dispersion compensation between the pump and the subharmonic waves. The EPR entangled state of light with quantum correlations of 8.4 dB for both amplitude and phase quadratures are experimentally produced by a single NOPA under the pump power of 75 mW. Am. B 6, 622-633 (1989). 32. A. Yariv, Quantum Electronics, 3rd edn. (Wiley, New York, 1988

Demonstration of Monogamy Relations for Einstein-Podolsky-Rosen Steering in Gaussian Cluster States

“…The transmissivities of output coupler at 540 nm and 1080 nm are 0.5% and 12.5%, respectively. In our experiment, all NOPAs are operated at the parametric deamplification situation [62,63]. Under this condition, the coupled modes at +45 • and −45 • polarization directions are thex-squeezed andp-squeezed states, respectively [63].…”

Quantification of quantum steering in a Gaussian Greenberger–Horne–Zeilinger state

“…The transmissivities of the front face of KTP crystal at 540 nm and 1080 nm are 21.2% and 0.04%, respectively. The end-face of KTP is cut to 1 • along y-z plane of the crystal and is antireflection coated for both 1080 nm and 540 nm [49]. The transmissivities of output coupler at 540 nm and 1080 nm are 0.5% and 12.5%, respectively.…”

Generating quantum correlated twin beams by four-wave mixing in hot cesium vapor

“…The standard technique to generate quantum correlated beams and continuous-variable entangled states is by parametric down-conversion in a nonlinear crystal, with an optical parametric oscillator (OPO) or optical parametric amplifier. While very large amounts of quantum noise reduction have been achieved in this way [6,7], the central frequency and linewidth of the generated nonclassical states usually do not naturally match the transitions of matters, such as atoms and solid-state systems, which limits their applications in light-matter interactions.…”