Optical limiting and bistability of a sigma-pi photoconductive copolymer

Optical nonlinearity of a sigma-pi photoconductive copolymer, poly(disilany lene-2, 2 ' -bipyridine-5, 5 ' -diyl) ruthenium complex, has been investiga ted in chloroform solution of various concentrations. The nonlinear optical absorption resulted in optical limiting, optical bistability, and laser pu lse compression for nanosecond pulses at the wavelength of 532 nm. Theoreti cal analyses showed that the optical absorptive nonlinearity was dependent on the photogenerated excitons and exciton-exciton couplings. (C) 2000 Else vier Science B.V. All rights reserved.