PERSISTENT SPECTRAL HOLEBURNING OF FRENKEL EXCITON SYSTEM WITH LARGE COHERENCE LENGTH - PIC(BR) J-AGGREGATES

We found unique burning power dependence in the hole formation of line ar Frenkel exciton system, J-aggregates of pseudo-isocyanine bromide, in water-ethylene glycol glasses at 4.7 K. With DC-laser light for bur ning, clear zero-phonon hole was formed with the width of 0.36 cm(-1). Once switching the laser for burning to the pulse mode operation, on the other hand, nano-second pulses e.g. can give rise to novel feature of dispersive lineshape of spectral change from the initial stage of burning: a broad and red-shifted (similar to 3 cm(-1) from the laser f requency omega(B)) non-resonant hole accompanied by antihole with simi lar size at shorter wavelength side. We consider the appearance of red -shifted nonresonant hole is essential in the present situation and is due to the two-exciton excitation through one-exciton transition by t wo-photon absorption. Based on this model, the shift of the hole is eq ual to half of the difference of k = 2 and k = 1 exciton energy, from which we can estimate the coherence length of N = 56 in the system.