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The ability to observe the buret of photons from single fluorescent molecules In solution with high efficiency (> 90%) Is a technically challenging task and has Important applications In many areas of analytical chemistry. The ability to observe the photon burst from visible fluorescent dye molecules using pulsed-laser excitation and time-gated detection In order to reduce the scattered photon contribution from the background has recently been demonstrated. The detectionefficiency of these molecules was limited due to the excitation of fluorescent Impurities resulting In small amplitude bursts observed In the solvent blank requiring the need for a high discriminator threshold to reduce the number of errors from false positives. We wish to reportthe first observation of the photon bursts arising from single near-infrared (near-IR) dye molecules transiting a focused Gaussian laser beam In solution with a high detection …