Picosecond photoinduced dichroism in trans-(CH)x: direct measurement of soliton diffusion

Photoinduced dichroism caused by bleaching of the interband transition in tran s-(CH)x was observed in the picosecond time domain,, The bleaching is induced instantaneously and decays with time as £~1 / / 2 , changing to a lower power after ~50 psec. Although the photoinduced bleaching persists to long times, polarization memory is lost after ~10"9 sec. The results provide a measurement of the diffusion constant of the charged excitations; D^ 2x 10"2 cm2 sec"1 at 300 and 80 K.