Lifetime identification of single molecules in aqueous solution
Zander C., Sauer M., Drexhage KH., Wolfrum JM., Brand L., Eggeling C., Seidel CAM.
Photon bursts of single rhodamine 6G and rhodamine B molecules in aqueous solution were studied by excitation with a frequency-doubled titanium: sapphire laser. Multichannel scalar traces, fluorescence correlation functions and fluorescence decays determined by time- correlated single-photon counting have been measured simultaneously. The time-resolved fluorescence signals were analyzed with a maximum likelihood estimator. With the setup described it is possible to distinguish single dye molecules of different kind via their characteristic fluorescence lifetimes of 1.79 +/- 0.33 ns for rhodamine B-zwitterion and 3.79 +/- 0.38 ns for rhodamine 6G. ©2005 Copyright SPIE - The International Society for Optical Engineering.