Investigation on third-order nonlinear optical properties of two Au(dmit)2/PMMA thin films by Z-scan technique in picosecond pulse regime

The third-order nonlinear optical properties of two Au(dmit)(2)/PMMA compound thin films, hexadecyltrimethylammonium bis(1,3-dithiole-2-thione-4,5-dithiolato)aurate and tetramethylammonium bis(1,3-dithiole-2-thione-4,5-dithiolato)aurate (abbreviated as MeAu and CtAu, respectively) with a doping concentration of 1 wt.% deposited on quartz-glass substrate were characterized by a single beam Z-scan technique at 1064 nm with 20 ps laser pulse width and 10 Hz repetition rate. The dominant nonlinear refraction and tiny nonlinear absorption of both materials lead to a larger possibility for them to be applied as promising candidates of all-optical switching. The results of two figures of merit, |W|a parts per thousand << 1 and |T|a parts per thousand(a)1, were also calculated; this further validated the excellent properties of the materials for applications of the nonlinear optics.