Observation of superradiant and subradiant spontaneous emission of two trapped ions

Summary form only given. We report a laboratory realization of the gedanken experiment that Dicke used to introduce superradiance. Two Ba/sup +/ ions are laser-cooled and crystallized in a microscopic Paul trap so that they come to rest 1.5 microns from each other. This is about 3 wavelengths of the 493 nm light used to laser cool the transition. Micromotion and residual thermal motion are low so that they are essentially stationary relative to 493 nm light.