EXPERIMENTAL-STUDY OF ENHANCED EMISSION OF THE LASER-ABLATED PLUME INBACKING GAS

The effects of background gases on the optical emission of the excimer -laser-ablated plume from a brass target have been studied experimenta lly. It is found that the plume emission can be enhanced significantly in a proper gas ambient. In hydrogen, the highest peak intensity is d etected, and in argon, there is a distinctive difference in the pressu re-dependent emission between in He and in the other three gases, Ar, N2 and H-2. Moreover, the monitored line peak intensity remains unchan ged in Ar and N2 and increases in H-2 within a distance above the targ et surface; but in He, the observed peak intensity decreases with dist ance like in vacuum. Furthermore, the emissions of several more atomic lines of Cu and Zn atoms from the plume are also found to be enhanced in the same manner in gas ambient. Some physical processes involved i n the plume expansion and the possible mechanisms for the enhanced emi ssion of the plume in backing gas are discussed.