Z-scan determination of third-order nonlinear optical nonlinearity of three azobenzenes doped polymer films

The third-order nonlinear response of methyl red (MR), methyl orange (MO) and p-dimethylamino benzene arsenic acid (PDBAA) doped polyvinyl alcohol (PVA) films are studied by using the Z-scan technique under 532 nm and 1064 nm excitations. The larger third-order nonlinear refractive index of PDBAA doped PVA film is discussed in terms of fall of the energy level in excited state for the effect of heavy-atom arsenic. At the end, the second hyperpolarizabilities of the films are estimated and the figures of merit are evaluated for their value of applications in ultra-fast all-optical devices.