diode laser A diode laser is a laser in which the active medium is a p-n junction semiconductor laser diode, similar to that found in a light-emitting diode. Laser diodes emit at wavelengths from 375 nm to 1800 nm, and wavelengths of over 3 micrometer have been demonstrated. A diode laser can by used to irradiate cells in a flow cytometer. FAX-RS3-H0 diode laser manufactured by Diode Laser Concepts, Inc. diode laser John Quinn Daniel Schober laser metadata incomplete