Experimental measurement of covariance matrix of two-mode entangled state  

作　　者：YU XuDong LI Wei JIN YuanBin ZHANG Jing 

机构地区：[1]State Key Laboratory of Quantum Optics and Quantum Optics Devices,Institute of Opto-Electronics,Shanxi University

出　　处：《Science China(Physics,Mechanics & Astronomy)》2014年第5期875-879,共5页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Basic Research Program of China(Grant No.2011CB921601);the National Natural Science Foundation of China(Grant No.11234008);the NSFC Project for Excellent Research Team(Grant Nos.61121064 and 11234008);Doctoral Program Foundation of the Ministry of Education China(Grant No.20111401130001)

摘　　要：A two-mode entangled state was generated experimentally through mixing two squeezed lights from two optical parametric amplifiers on a 50/50 beam splitter.The entangled beams were measured by means of two pairs of balanced homodyne detection systems respectively.The relative phases between the local beams and the detected beams can be locked by using the optical phase modulation technique.The covariance matrix of the two-mode entangled state was obtained when the relative phase of the local beam and the detected beam in one homodyne detection system is locked and the other is scanned.This method provides a way by which one can extract the covariance matrix of any selected quadrature components of two-mode Gaussian state.A two-mode entangled state was generated experimentally through mixing two squeezed lights from two optical parametric am- plifiers on a 50/50 beam splitter. The entangled beams were measured by means of two pairs of balanced homodyne detection systems respectively. The relative phases between the local beams and the detected beams can be locked by using the optical phase modulation technique. The covariance matrix of the two-mode entangled state was obtained when the relative phase of the local beam and the detected beam in one homodyne detection system is locked and the other is scanned. This method provides a way by which one can extract the covariance matrix of any selected quadrature components of two-mode Gaussian state.

关 键 词：optical parametric amplifier Gaussian entangled state covariance matrix 

分 类 号：O431.2[机械工程—光学工程]