Picosecond nonlinear optical studies of unsymmetrical alkyl and alkoxy phthalocyanines

We present our results on picosecond nonlinearities in unsymmetrical alkyl and alkoxy phthalocyanines, studied using the Z-scan technique. Both open and closed aperture Z-scan curves were recorded and nonlinear coefficients were extracted. Solvent contribution to the nonlinearity was identified. We recorded large, off-resonant second hyperpolarizabilities (γ) at 800 nm with estimated values of ∼ 6.5 × 10⁻³¹ esu and ∼ 8.9 × 10⁻³¹ esu for unsymmetrical alkyl and alkoxy phthalocyanines, respectively. Evaluated figures of merit indicate that these are potential molecules for photonic applications.