STUDY OF THE EFFECTS OF MEV AG AND AU IMPLANTATION ON THE OPTICAL-PROPERTIES OF LINBO3

We present the results of characterization of linear absorption and no nlinear refractive index of Au and Ag nanoclusters made by MeV ion imp lantation into LiNbO3, Ag was implanted at 1.5 MeV to fluences of 2 to 17 x 10(16)/cm(2) at room temperature. Au was implanted to fluences o f 5-20 x 10(16)/cm(2) at an energy of 2.0 MeV. Optical absorption spec trometry indicated an absorption peak at 560 nm for the Au implanted s amples after a 30 min heat treatment at 500 degrees C in air. The peak shifted to similar to 620 nm after heat treatment at 1000 degrees C. The Ag implanted samples had absorption peaks at 445-485 nm before hea t treatment. After 500 degrees C heat treatment for 1 h the peaks decr eased in height and shifted from 545 to 560 nm. Heat treatment at 800 degrees C was sufficient to return the Ag implanted crystals to a dear state. The size of the clusters was determined from the absorption pe aks. The Ag clusters did not change appreciably in size with heat trea tment. The Au clusters increased from 1 to 3 nm upon heat treatment at 1000 degrees C. Measurements of the nonlinear refractive indices were carried out using the z-scan method with a tunable dye laser pumped b y a frequency doubled mode-locked Nd:YAG laser. The dye laser had a 4. 5 ps pulse duration time and 76 MHz pulse repetition rate (575 nm). (C ) 1998 Elsevier Science B.V. All rights reserved.