The absorption spectrum and the laser-induced luminescent spectrum of dysprosium-acetylacetone-tri-n-octylphosphine oxide (Dy-AA-TOPO) in the micellar solution of anionic surfactant sodium lauryl sulfo-nate (SLS) were studied using homemade laser fluorimeter. Basic components of experimental apparatus for laser fluorimeter are an actively Q-switched Nd:YAG-pumped dye laser as the excitation light source

a SIT vidicon optical multichannel analyzer as the luminescence detecting equipment and an electric trigger made by our laboratory as the external trigger source. The phosphorescent emission of AA was determined for the first time at room temperature. The luminescence mechanism and a two-step energy transfer process are proposed.The energy transfers from the donor TOPO to the acceptor AA and from the donor AA to the acceptor dysprosium ion. The AA acts both the donor and the acceptor.Dy-AA*-TOPO*-Dy*-AA*-TOPO-Dy*-AA-TOFO+

hv

-Dy-AA-TOPO+

hv

The Dy-AA-TOPO-SLS system is adopted in the determination of the trace dysprosium. The calibration curve is linear over the range of 1-200 ng Dy/ml. A new sensitive fluorescence phenomenon is observed by adding some of metal ions

which is named synergistic luminescence. Results are setisfactory for the determination of dysprosium in highly pure ytterbium oxide and synthetic samples without pre-separation.