Spatially modulated fluorescence emission from moving particles

An optical detection technique for a flow cytometer is described, which delivers high signal-to-noise discrimination without precision optics to enable a flow cytometer that can combine high performance, robustness, compactness, low cost, and ease of use. The enabling technique is termed "spatially modulated emission" and generates a time-dependent signal as a continuously fluorescing bioparticle traverses a predefined pattern for optical transmission. Correlating the detected signal with the known pattern achieves high discrimination of the particle signal from background noise. The technique is demonstrated with measurements of fluorescent beads flowing through a microfluidic chip.