Two-photon absorption spectrum of oriented trans-polyacetylene

Abstract

The two-photon absorption spectrum of oriented trans-polyacetylene was measured from 0.55 to 0.96 eV using nonlinear photothermal deflection spectroscopy. The major two-photon absorption resonance is at 0.55 eV; at the peak, Im χ (3) | (−ω; ω, −ω, ω)=1.6×10 −7 esu where Imχ (3) |) is the imaginary part of the third order nonliner optical susceptibility for pump fields along the chain axis. There is an additional two-photon absorption resonance (narrower and weaker) at 0.8 eV. Although Imχ (3) |) limits the use of polyacetylene in serial optical computer architectures, a parallel architecture with short optical pathlengths can be used with considerable advantage.