Title :
Sub-5-fs real-time spectroscopy of coherent geometrical relaxation processes in polydiacetylenes
Author :
Kobayashi, T. ; Shirakawa, A. ; Matsuzawa, H. ; Nakanishi, H.
Author_Institution :
Dept. of Phys., Tokyo Univ., Japan
Abstract :
Summary form only given. Ultrafast dynamics of conjugated polymers such as polydiacetylenes (PDA) has been attracting many scientists because they are model systems of quasi-one dimensional semiconductors with a strong electron-phonon coupling. From our extensive studies the initial kinetics after photo-excitation can be explained by a relaxation of a free exciton (FE) to a self-trapped exciton (STE) within 150 fs. The recent achievement of sub-5-fs visible pulse generation based on a novel noncollinear optical parametric amplification (NOPA) has enabled the real-time observation of the formation of a STE in a PDA for the first time.
Keywords :
electron-phonon interactions; excitons; high-speed optical techniques; optical parametric amplifiers; optical polymers; optical pulse generation; 150 fs; 5 fs; coherent geometrical relaxation processes; conjugated polymers; free exciton relaxation; fs visible pulse generation; initial kinetics; noncollinear optical parametric amplification; photo-excitation; polydiacetylenes; quasi-one dimensional semiconductors; real-time observation; self-trapped exciton; strong electron-phonon coupling; sub fs real-time spectroscopy; ultrafast dynamics; Excitons; Iron; Kinetic theory; Nonlinear optics; Optical pulse generation; Polymers; Pulse generation; Spectroscopy; Stimulated emission; Ultrafast optics;
Conference_Titel :
Quantum Electronics and Laser Science Conference, 1999. QELS '99. Technical Digest. Summaries of Papers Presented at the
Conference_Location :
Baltimore, MD, USA
Print_ISBN :
1-55752-576-X
DOI :
10.1109/QELS.1999.807533
