We report real-time observation of fluorescence bursts from individual Rhodamine 6G molecules in streams of microdroplets (peak signal-to-noise ratios, ≈30) whose trajectories are constrained with a linear electric quadrupole. This approach offers a reasonable dynamic range in droplet size (3– 12-µm diameter) with <1% shot-to-shot size fluctuations and sensitivity comparable with that of droplet levitation techniques with at least 103 higher analysis rates. Applications to the study of single-molecule microcavity effects and stimulated emission are discussed.
© 1997 Optical Society of America
M. D. Barnes, N. Lermer, C.-Y. Kung, W. B. Whitten, J. M. Ramsey, and S. C. Hill, "Real-time observation of single-molecule fluorescence in microdroplet streams," Opt. Lett. 22, 1265-1267 (1997)