Open AccessOptical percolation and nonlinearity of sputtered Ag island films
Author(s) -
Sha Ding,
X. Wang,
D. J. Chen,
Q. Q. Wang
Publication year - 2006
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.14.001541
Subject(s) - transmittance , materials science , percolation (cognitive psychology) , percolation threshold , optics , attenuation coefficient , absorption (acoustics) , absorbance , wavelength , microstructure , condensed matter physics , analytical chemistry (journal) , molecular physics , composite material , physics , optoelectronics , electrical resistivity and conductivity , chemistry , chromatography , quantum mechanics , neuroscience , biology
The fractal dimension Df and the critical parameter nu of the sputtered percolation Ag island films are measured to be about 1.57 and 1.15, respectively. A modified Z-scan method including both transmittance Z-scan and reflection Z-scan is proposed to measure the pure nonlinear absorption of the semi-continuous Ag films near the percolation threshold. As the microstructure of the sputtered Ag films varies from the discontinuous to the continuous, the linear absorbance decreases from 0.97 to 0.58 while the nonlinear absorption coefficient changes from -1.4x10-5m/W to -4.6x10-6m/W at the wavelength of 800nm. The largest nonlinear absorption coefficient beta of the sputtered Ag films is obtained in the discontinuous film near the percolation threshold, which is mainly contributed by the large enhancement of local field of dis-continuous Ag particles.