Excitation of a breather mode of bound soliton pairs in trans-polyacetylene by sub-five-femtosecond optical pulses.
Trans-polyacetylene with a degenerate ground state has a nonlinear excitation of soliton after photoexcitation, due to the electron-phonon coupling. The excess energy of an excited electron-hole pair over a soliton pair creation induces a breather oscillation characterized by collective stretching vibration of the carbon-carbon bonds. A time-frequency analysis of pump probe signal shows that instantaneous frequencies of stretching modes are modulated for approximately 50 fs after excitation and the modulation period is 44+/-3 fs consistent with the theoretical expectation, clearly verifying the breather.
Adachi
Shunsuke
S
Department of Physics, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan.
Kobryanskii
Valerii M
VM
Kobayashi
Takayoshi
T