Cross-correlation technique for dispersion characterization of chirped volume Bragg gratings.

We propose using cross-correlation frequency-resolved optical gating for dispersion characterization of optical elements with high dispersion, such as ultrashort pulse stretchers and compressors. The technique is based on spectrally resolved second-order cross correlation (sum frequency generation) of a stretched pulse with a reference short pulse. Dispersion of optical elements with a high pulse stretching ratio can be completely characterized using this method, even with moderate resolution of spectral measurements of the cross-correlation signal.

Solvent effects on the three-photon absorption cross-section of a highly conjugated fluorene derivative.

Herein, we report the study of the three-photon absorption cross-section dependence on solvents parameters for a highly conjugated organic dye, 2,2'-(4,4'-(1E,1'E)-2,2'-(9,9-didecyl-9H-fluorene-2,7-diyl) bis(ethene-2,1-diyl)bis(4,1-phenylene))dibenzo[d]thiazole (A-pi-pi-pi-A). The three-photon absorption cross-section was measured for this organic dye in solution in four different solvents with polarity function, Deltaf between 0.162 and 0.

Surface plasmon enhancement of two- and three-photon absorption of Hoechst 33 258 dye in activated gold colloid solution.

Herein we present experimental evidence of the strong surface plasmon enhancement of two- and three-photon absorption of Hoechst 33 258 (2'-(4-hydrophenyl)-5-(4-methyl-1-piperazinyl)-2,5'-bis(1H-benzimidazole)) pentahydrate in an aqueous solution containing activated gold colloid. The 480-fold enhancement in two-photon absorption and 30-fold in three-photon absorption are predominantly attributed to the electric-field enhancement via surface plasmon resonance. The greater enhancement observed in two-photon absorption is due to the characteristic two- and three-photon absorption cross-sections of the dye.

The impact of the pi-electron conjugation length on the three-photon absorption cross section of fluorene derivatives.

The three-photon absorption cross sections of three different fluorene derivatives, with extended pi-electron conjugation lengths was experimentally measured and compared with shorter pi-electron conjugation length analogs. The effect of the conjugation length on the three-photon absorption cross section sigma(3) (') of this family of molecules has been elucidated. It is demonstrated that sigma(3) (') of the asymmetric compound D-pi-pi-pi-A is 6.

Mega three-photon absorption cross-section enhancement in pseudoisocyanine J-aggregates.

Herein we report an extraordinary three-photon absorption cross-section (sigma'3) enhancement in J-aggregates supramolecular systems. The much higher value of sigma'3 in PIC J-aggregate (2.5 x 10(-71) cm6 s2 ph(-2)) compared to typical values obtained in organic molecules (10(-80) cm6 s2 ph(-2)) is attributed to the strong molecular transition dipole moment coupling in the supramolecular assembly.