中国物理B ›› 2009, Vol. 18 ›› Issue (10): 4143-4153.doi: 10.1088/1674-1056/18/10/013

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Einstein--Podolsky--Rosen entanglement in time-dependent periodic pumping non-degenerate optical parametric amplifier

谭维翰1, 赵超樱2   

  1. (1)Department of Physics, Shanghai University, Shanghai 200444, China; (2)Institute of Materials Physics, Hangzhou Dianzi University, Hangzhou 310018, China;The State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, China
  • 收稿日期:2008-07-03 修回日期:2008-12-30 出版日期:2009-10-20 发布日期:2009-10-20
  • 基金资助:
    Project supported by the Natural Science Foundation of Shanxi Province, China (Grant No 2006011003).

Einstein--Podolsky--Rosen entanglement in time-dependent periodic pumping non-degenerate optical parametric amplifier

Zhao Chao-Ying(赵超樱)a)b)† and Tan Wei-Han(谭维翰)c)   

  1. a Institute of Materials Physics, Hangzhou Dianzi University, Hangzhou 310018, China; b The State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, China; c Department of Physics, Shanghai University, Shanghai 200444, China 
  • Received:2008-07-03 Revised:2008-12-30 Online:2009-10-20 Published:2009-10-20
  • Supported by:
    Project supported by the Natural Science Foundation of Shanxi Province, China (Grant No 2006011003).

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摘要： The solution of the time-dependent periodic pumping non-degenerate optical parametric amplifier (NOPA) is derived when the pump depletion is considered both above and below thresholds. Based on this solution, the quantum fluctuation calculated shows that a high entanglement and a good squeezing degree of the parametric light beams are achieved near and above thresholds. We adopt two kinds of pump fields: (i) a continuously modulated pump with a sinusoidal envelope; (ii) a sequence of laser pulses with Gaussian envelopes. We analyse the time evolution of continuous variable entanglement by analytical and numerical calculations, and show that the periodic driven pumping also improves the degree of entanglement. The squeezing and Einstein-Podolsky-Rosen (EPR) entanglement by using the two pumping driven functions are investigated from below to above the threshold regions, the tendencies are nearly the same, and the Gaussian driven function is superior to that of the sine driven function, when the maximum squeezing and the minimum variance of quantum fluctuation are considered. In the meantime, the generalization of frequency degenerate OPA to frequency non-degenerated OPA problem is investigated.

Abstract: The solution of the time-dependent periodic pumping non-degenerate optical parametric amplifier (NOPA) is derived when the pump depletion is considered both above and below thresholds. Based on this solution, the quantum fluctuation calculated shows that a high entanglement and a good squeezing degree of the parametric light beams are achieved near and above thresholds. We adopt two kinds of pump fields: (i) a continuously modulated pump with a sinusoidal envelope; (ii) a sequence of laser pulses with Gaussian envelopes. We analyse the time evolution of continuous variable entanglement by analytical and numerical calculations, and show that the periodic driven pumping also improves the degree of entanglement. The squeezing and Einstein-Podolsky-Rosen (EPR) entanglement by using the two pumping driven functions are investigated from below to above the threshold regions, the tendencies are nearly the same, and the Gaussian driven function is superior to that of the sine driven function, when the maximum squeezing and the minimum variance of quantum fluctuation are considered. In the meantime, the generalization of frequency degenerate OPA to frequency non-degenerated OPA problem is investigated.

Key words: EPR entanglement, periodic pumping, non-degenerate optical parametric amplifier

中图分类号:  (Optical parametric oscillators and amplifiers)

  • 42.65.Yj
42.50.Dv (Quantum state engineering and measurements)