Reverse Saturable Absorption in Substituted Hydrazones and Its Structure-Property Relationship for Photonic Applications

The third-order nonlinear optical properties of three hydrazone derivatives, namely, ethyl 2-((2E)-2-(4-(dimethylamino)benzylidene]hydrazinyl)-5-nitrobenzoate, ethyl 2-((2E)-2-(4-chlorobenzylidene)hydrazino)-5-nitrobenzoate, and methyl 5-nitro-2-((2E)-2-(4-nitrobenzylidene)hydrazino)benzoate were investigated by the single beam Z-scan technique with nanosecond laser pulses at 532 nm. The compounds were doped into PMMA (poly (methyl methacrylate)), and their third-order nonlinearity was studied with a prospective of reaching a compromise between processability and high nonlinear optical behavior. The optical limiting study of the samples was carried out at 532 nm. The measured values of the third-order nonlinear susceptibility, χ(3), and the nonlinear refractive index, n 2 , are of the order of 10 − 13   esu and 10 − 11   esu , respectively. The nonlinear absorption in materials was attributed to reverse saturable absorption. The results are quite promising for possible applications in photonic devices.