Abstract: Methods and systems are described for determining information about template sequences by simultaneously providing excitation over time to a plurality of confined sources on a substrate, each confined source carrying out a template mediated addition of nucleotides with a polymerase enzyme. The nucleotides have different labels, each with a different emission wavelength profile. Optical elements direct optical signals from the different NTPs within each optical confinement to different detector locations. Observing the optical signals over time allows for obtaining sequence information about the template nucleic acids.