(a) Structure of the phthalocyanine whose nanoparticles were studied. (b) TEM image of the nanoparticles dispersed in water.
Absorption spectra of PcN in water (solid curve), PcN in chloroform resulting in PcM (dashed curve), and pure phthalocyanine in chloroform (dotted curve).
Emission spectra of PcM and PcN (a) excited with 300 and 330 nm, respectively, and (b) excited with 650 nm.
(a) Open aperture Z-scan data (open circles) for PcM in chloroform obtained for an intensity of . Solid line is the best fit. [(c) and (d)] Open aperture Z-scan curves obtained for PcM at different intensities.
Open aperture data for PcN in water indicating the presence of three-photon absorption. Inset shows the closed aperture data representing positive nonlinearity.
Optical limiting curve obtained for PcM (open circles) and PcN (open squares) dispersed in water and dissolved in chloroform, respectively. Solid line is the linear transmittance curve.
Two-photon absorption coefficients , three-photon absorption coefficients , nonlinear refractive indices , and clamping thresholds of the phthalocyanines excited with 800 nm wavelength, 110 fs pulses.
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