Patent ID: 8535938

Claim:
A system for sorting a mixture of particles, including stained sperm cells having either characteristic A or characteristic B, into at least one population, the system comprising: a. a fluid delivery system for delivering a fluid stream containing the stained sperm cells in a flow path; b. an electromagnetic radiation source for exciting fluorescence emissions from the stained sperm cells having characteristic A and the stained sperm cells having characteristic B in the flow path, wherein the electromagnetic radiation source comprises a pulsed laser; c. a photodetector for detecting the fluorescence emissions from stained sperm cells having characteristic A and stained sperm cells having characteristic B; d. an epi-illumination optics system including a focusing lens, the optics system positioned to direct electromagnetic radiation produced by the pulsed laser through the focusing lens in a forward direction along a beam axis, wherein the beam axis is incident upon the fluid stream at a skewed angle, and wherein said skewed angle comprises an angle of incidence other than 90 degrees; e. a processor in communication with the photodetector for classifying the stained sperm cells in the flow path according to their fluorescence emissions as either sperm cells having characteristic A or sperm cells having characteristic B; f. a control in communication with the photodetector for selecting sperm cells to damage according to their classification to produce an enriched population of sperm cells with respect to either characteristic A or characteristic B; and g. a photo-damaging laser in communication with the control for ablating the selected sperm cells in the flow path.