A method comprising: emitting with a light energy exciter excitation light, wherein the light energy exciter comprises a first light source and a second light source, the first light source to emit excitation light rays in a green wavelength emission band, the second light source to emit excitation light rays in a blue wavelength emission band; receiving with a detector the excitation light and emissions signal light resulting from excitation by the excitation light, the detector comprising a detector surface for supporting biological or chemical samples and a sensor array spaced apart from the detector surface, the detector blocking the excitation light and permitting the emissions signal light to propagate toward light sensors of the sensor array; and transmitting with circuitry of the detector data signals in dependence on photons sensed by the light sensors of the sensor array; wherein the method comprises for each of a plurality of cycles in support of a DNA sequencing process (a) removing fluid from a flow cell defined by the detector surface, (b) filling the flow cell with a fluid having at least three fluorophores, (c) reading out first signals from the light sensors exposed to emissions signal light with the first light source energized and the second light source maintained in a deenergized state, (d) reading out second signals from the light sensors exposed to emissions signal light with the second light source energized and the first light source maintained in a deenergized state, and (e) identifying a DNA nucleotide using signals of the first signals and signals of the second signals, comprising: determining that a first fluorophore is attached to a sample based on fluorescence being detected in step (c) but not in step (d); determining that a second fluorophore is attached to a sample based on fluorescence being detected in step (d) but not in step (c); determining that a third fluorophore is attached to a sample based on fluorescence being detected in both step (c) and step (d). emitting with a light energy exciter excitation light, wherein the light energy exciter comprises a first light source and a second light source, the first light source to emit excitation light rays in a green wavelength emission band, the second light source to emit excitation light rays in a blue wavelength emission band; receiving with a detector the excitation light and emissions signal light resulting from excitation by the excitation light, the detector comprising a detector surface for supporting biological or chemical samples and a sensor array spaced apart from the detector surface, the detector blocking the excitation light and permitting the emissions signal light to propagate toward light sensors of the sensor array; and transmitting with circuitry of the detector data signals in dependence on photons sensed by the light sensors of the sensor array; wherein the method comprises for each of a plurality of cycles in support of a DNA sequencing process (a) removing fluid from a flow cell defined by the detector surface, (b) filling the flow cell with a fluid having at least three fluorophores, (c) reading out first signals from the light sensors exposed to emissions signal light with the first light source energized and the second light source maintained in a deenergized state, (d) reading out second signals from the light sensors exposed to emissions signal light with the second light source energized and the first light source maintained in a deenergized state, and (e) identifying a DNA nucleotide using signals of the first signals and signals of the second signals, comprising: determining that a first fluorophore is attached to a sample based on fluorescence being detected in step (c) but not in step (d); determining that a second fluorophore is attached to a sample based on fluorescence being detected in step (d) but not in step (c); determining that a third fluorophore is attached to a sample based on fluorescence being detected in both step (c) and step (d). (a) removing fluid from a flow cell defined by the detector surface, (b) filling the flow cell with a fluid having at least three fluorophores, (c) reading out first signals from the light sensors exposed to emissions signal light with the first light source energized and the second light source maintained in a deenergized state, (d) reading out second signals from the light sensors exposed to emissions signal light with the second light source energized and the first light source maintained in a deenergized state, and (e) identifying a DNA nucleotide using signals of the first signals and signals of the second signals, comprising: determining that a first fluorophore is attached to a sample based on fluorescence being detected in step (c) but not in step (d); determining that a second fluorophore is attached to a sample based on fluorescence being detected in step (d) but not in step (c); determining that a third fluorophore is attached to a sample based on fluorescence being detected in both step (c) and step (d). determining that a first fluorophore is attached to a sample based on fluorescence being detected in step (c) but not in step (d); determining that a second fluorophore is attached to a sample based on fluorescence being detected in step (d) but not in step (c); determining that a third fluorophore is attached to a sample based on fluorescence being detected in both step (c) and step (d).