Photons emanating from a channel in a fluidic structure or from moving objects are sensed using a photosensor array in an integrated circuit. The array includes subrange cells that photosense within respective subranges of a photon energy range. For example, the subrange cells can receive photons in their respective subranges from a transmission structure that has laterally varying properties. The photons can be emitted in response to excitation or can be scattered in response to illumination.