Monte Carlo simulation of a single-molecule detection experiment

The physical and instrumental processes that occur in experiments for the detection of individual fluorescent molecules in solution are described, with emphasis on their incorporation into a quantitative Monte Carlo simulation. The simulation is applied to the conditions of a past experiment [Appl. Opt. 34, 3208 (1995)], which utilizes a sheath flow system for high detection efficiency, and it generates comparable results, while helping to identify experimental limitations. The simulation indicates that the use of low dead-time electronics and appropriate selection of experimental parameters should enable detection at more rapid rates for applications in which large numbers of molecules are to be efficiently counted. (C) 1998 Optical Society of America.