Optical nonlinear refractive and limiting behavior of nickel complex dye doped solid-state matrix for both visible and near infra-red nanosecond excitations

The present work focuses on the investigations for laser induced third order nonlinear optical response in nickel-complex bis(4-dimethylaminodithiobenzyl)-nickel (BDN) dye encapsulated in poly(methylmethacrylate) (PMMA) matrix under excitation with nanosecond laser pulses at two different wavelengths of 532 nm and 1064 nm. Intensity dependent absorption coefficient, nonlinear refractive index and cubic nonlinear susceptibility are estimated using Z-scan technique. The observed nonlinearity with nanosecond excitation is of thermal origin. Nonlinear change in refraction attributes to self-defocusing due to two-photon absorption. Optical limiting behavior is characterized by the limiting threshold and dynamic range parameters. Existence of strong third order nonlinearity with quite low limiting threshold for both visible and near infra-red laser pulses confirms that BDN doped solid-state samples have a great potential for the applications as broad band optical limiter.