Experimental characterization of two-photon materials for fast rewritable optical data storage

We study one photon absorption (IPA) and two photon absorption (2PA) properties of a series of asymmetrical phthalocyanines for 2PA-based 3D optical information storage. These compounds show very large 2PA cross section, 10(3) - 10(4) GM, in near IR range of excitation, from 800 to 900 nm. This strong resonance enhancement effect is possible due to one-photon-allowed and narrow intermediate Q-transition, occurring in very vicinity of excitation wavelength. We report 2PA spectra, 2PA cross-sections, temperature stability, tautomerization and fluorescence quantum yields, measured in organic solvents and in polymer films in temperature range 77 - 300K. We show that the unique combination of photophysical properties make these compounds attractive candidates for fast re-writable volumetric storage.