量子光学基础课件.ppt

BEA Confidential * BEA Confidential * BEA Confidential. | * Chapter Three Ocean University of China Content: 一维光腔中光场的量子化 3.1 J-C模型 3.3 相干态光场 3.2 Ocean University of China 3.1 一维光腔中光场的量子化（quantization） Ocean University of China L z 0 Ocean University of China Ocean University of China Ocean University of China 3.2 相干态 （coherent state) Ocean University of China 激光可看作处于相干态。由于相干态是Fock态的叠加态，激光脉冲中的光子数是不确定的。 平均光子数： 光子数分布（含n个光子的概率）： 即满足泊松分布。 问题：在量子密码通信中，常采用经衰减的激光脉冲作为单光子源。若要求出现两个以上光子的概率小于1%以保证安全性，试估算要将激光的强度（平均光子数）降到多少？ Ocean University of China Ocean University of China 3.3 J-C模型（Janes-Cummings） Ocean University of China 二能级原子 Ocean University of China Ocean University of China Ocean University of China Ocean University of China Ocean University of China Thank You BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential BEA Confidential. | * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential * BEA Confidential *