Multiphoton absorption mechanism of TMTTF, its radical cation and soluble single wall carbon nanotubes

Non linear absorption is a non linear optical property which can be observed with large photon intensities and corresponds to instantaneous or sequential absorption of more than one photon. Highly polarisable Molecules show high non linear optical activity and in the following it will be presented the multiphoton absorption properties of tetramethyltetratiafulvalene (TMTTF), its radical cation and pristine and Soluble single wall carbon nanotubes (SWNT). One finds that excited two photon absorptions are active for nanosecond laser pulses at 532 run with very large absorption cross sections.