Second-harmonic generation from axially substituted indium phthalocyanines

The quadratic hyperpolarizabilities of three axially substituted Indium pht halocyanines (Tn-Pcs) (1-3) in chloroform solution have been measured by th e EFISH technique at lambda = 1064 nm. A maximum value of 37.4 x 10(-30) es u has been obtained for the trifluoromethylphenyl-substituted compound 3. T he data have been analyzed with a two-level model corresponding to the Q-ba nd and so the nonresonant values for the quadratic hyperpolarizability, bet a(z)(0), have been determined by taking into account the electronic contrib ution to gamma(EFISH). The three components chi(15)((2)), chi(31)((2)), and chi(33)((2)) and of the susceptibility tensor have also been obtained for spin-coated films containing the three compounds dissolved in PMMA. Suscept ibilities reach the highest values, chi(15)((2)) = 3.3 x 10(-10) esu, chi(3 1)((2)) = 3.9 x 10(-10) esu, and chi(33)((2)) = 13.1 x 10(-10) esu, for com pound 3. Kleinman symmetry is approximately obeyed particularly for the Cl- substituted compound 1.