1. An optical and detection system for a flow cytometer having a flow channel with an interrogation zone and an illumination source that impinges the interrogation zone from a particular direction, the optical system comprising: a lens subsystem including: a collimating element that receives and collimates light from the interrogation zone; a light dispersion element that disperses the collimated light into a continuous wavelength spectrum of light; and a focusing lens that focuses the spectrum of light onto an array of adjacent detection points; and a plurality of contiguous detectors that detect light at the adjacent detection points.