Structural tuning effect to enhance the nonlinear optical response of salen type compounds.

Third order nonlinear optical properties of salen Schiff base complexes (1-4) functionalized with different electron donor acceptor groups (DA groups) were investigated in solution state via Z-Scan technique with Nd;YAG laser source. Among the two different complexes (Ni(II) and Cu(II)), having same DA ligands; the one with Cu(II) centre shows highest response. Also, the ligand having extended π-conjugation exhibit highest third order NLO activity. Electron donating substituent present in the imine spacer also affects the nonlinear response of the compound and also indicates that nonlinear optical (NLO) response of an inorganic material can be fine-tuned by the proper selection of central metal atom as well as the organic counterpart. [ABSTRACT FROM AUTHOR]