单分子的光学探测

Optics detection of single molecules

介绍了三能级结构单分子光子源的工作原理,研究了利用Hanbury-Brown-Twiss探测方法,记录两个单光子计数器响应的单分子光子源输出的每一个事件,分析单事件的光子统计概率P(n,n=0,1,2)与Mandel参数.研究结果表明,当信号背景比SBR>2.41时,P(2)<(2-4-2n-)2/2是判别单分子的充分条件,n-为每个激发周期内探测到的平均光子数.

The principle of single photon source based on three-levels single molecule is introduced. By use of Hanbury-Brown-Twiss method, the photon statistics P（n, n = 0,1,2） and the Mandel parameter are analyzed by recording of every photo-electrical event from the single photon source. When signal to background ratio SBR 〉 2. 4, an efficient method to distinguish single molecules by the double-photon statistics probability P （2）, which shows P（2） 〈 1/2 （2 -√4 -2n^-）^2 , is presented. Here, n is the mean photon number.