Femtosecond nonlinear optical dynamics of excitons in J-aggregates

✍ Scribed by Kaoru Minoshima; Makoto Taiji; Kazuhiko Misawa; Takayoshi Kobayashi

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 523 KB
• Volume: 218
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(93)e1464-r

✦ Synopsis

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 2 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.