Abstract: The invention comprises a method for determining a nucleotide sequence of a polynucleotide. In some embodiments, the method comprises providing a solid state substrate comprising a cis side and a trans side. The fluorescently labeled polynucleotide strand comprises (i) a proximal end that is attached to the carrier particle, (ii) a distal end that is cleavable by an exonuclease, and (iii) at least one fluorescently labeled nucleotide comprising a fluorescent label. The trans side of the substrate is illuminated with excitation light to create a fluorescence excitation zone. While the substrate is illuminated, the fluorescently labeled polynucleotide strand is reacted with an exonuclease so that mononucleotides are released serially from the distal end of the strand and diffuse through the fluorescence excitation zone, so that fluorescently labeled mononucleotides in the excitation zone emit fluorescent signals.