Femtosecond nonlinear optical dynamics of excitons in J-aggregates

Time-resolved difference absorption spectra of J-aggregates were measured by femtosecond pump-probe spectroscopy. The induced absorption near the J-band at 20 K was assigned to the transitions from n-exciton states to (n + 1)-exciton states (n⩾1). The decay time of the n(⩾2)-exciton states is determined to be about 200 fs. The ultrafast dynamics of the exciton states is explained by a confined exciton model in individual coherent aggregates, which incoherently constitute the whole structural aggregate. The average size of the exciton system defined for each coherent aggregate is estimated to be about 20 molecules.

[1]  Alan E. Johnson,et al.  Pump-probe spectroscopy and exciton dynamics of J aggregates at high pump intensities , 1993 .

[2]  E. Knapp.  Lineshapes of molecular aggregates, exchange narrowing and intersite correlation , 1984 .

[3]  Takayoshi Kobayashi,et al.  FEMTOSECOND STUDIES OF PRIMARY PHOTOPROCESSES IN OCTOPUS RHODOPSIN , 1992 .

[4]  Spanò,et al.  Nonlinear susceptibilities of molecular aggregates: Enhancement of chi (3) by size. , 1989, Physical review. A, General physics.

[5]  Jasper Knoester,et al.  Optical properties of disordered molecular aggregates: a numerical study , 1991 .

[6]  W. Kaiser,et al.  Ultrafast transient processes of monomers, dimers, and aggregates of pseudoisocyanine chloride (PIC) , 1982 .

[7]  Ying Wang.  Resonant third-order optical nonlinearity of molecular aggregates with low-dimensional excitons , 1991 .

[8]  W. Kaiser,et al.  The first step of aggregation of pic: the dimerization , 1981 .

[9]  P. Scherer,et al.  On the theory of vibronic structure of linear aggregates. Application to pseudoisocyanin (PIC) , 1984 .

[10]  D. Wiersma,et al.  Optical Dynamics of Condensed Molecular Aggregates : An Accumulated Photon-Echo and Hole-Burning Study of the J-Aggregate , 1987 .

[11]  J. Friedrich,et al.  A hole burning study of excitonic states of chain molecules in glasses , 1989 .

[12]  EDWIN E. JELLEY,et al.  Spectral Absorption and Fluorescence of Dyes in the Molecular State , 1936, Nature.

[13]  H. Fidder,et al.  SUPERRADIANT EMISSION AND OPTICAL DEPHASING IN J-AGGREGATES , 1990 .

[14]  Takayoshi Kobayashi,et al.  The biexcitonic quenching and exciton migration rate in aromatic crystals , 1972 .

[15]  H. Fidder,et al.  Observation of the one‐exciton to two‐exciton transition in a J aggregate , 1993 .

[16]  R. Gadonas,et al.  Annihilation of singlet excitons in J aggregates of pseudoisocyanine (PIC) studied by pico‐ and subpicosecond spectroscopy , 1988 .

[17]  Ying Wang.  Efficient second-harmonic generation from low-dimensional dye aggregates in thin polymer film , 1986 .

[18]  D. Wiersma,et al.  Dephasing-induced damping of superradiant emission in J-aggregates , 1990 .

[19]  H. Fidder,et al.  Dynamics of Frenkel excitons in disordered molecular aggregates , 1991 .

[20]  D. B. Chesnut,et al.  Fermion Behavior of One‐Dimensional Excitons , 1963 .