Bright three-color continuous-variable (CV) entanglement generated by a cascaded sum-frequency process in an optical cavity is investigated. The second- and fourth-harmonic beams can be generated by two quasi-phase-matched cascaded sum-frequency processes in a quasi-periodic optical superlattice. Quantum correlations among the fundamental and second- and fourth-harmonic beams are calculated and discussed by applying a sufficient and necessary inseparability criterion for CV three-mode entanglement. Strong three-color CV entanglement beams with a double frequency interval can be produced in this simple system. It is experimentally feasible and may be very useful for applications in quantum communication and computation networks.
© 2011 Optical Society of America
Original Manuscript: January 24, 2011
Revised Manuscript: June 20, 2011
Manuscript Accepted: June 20, 2011
Published: July 14, 2011
Youbin Yu and Huaijun Wang, "Bright three-color continuous-variable entanglement generated by a cascaded sum-frequency process in an optical cavity," J. Opt. Soc. Am. B 28, 1899-1904 (2011)