Optical third-harmonic generation in polyacetylene

Third-harmonic generation experiments have been performed on fully oriented crystalline ItransR-(CH)ₓ Rat two laser wavelengths: 1.064 and 1.907 {μ}m. Theoretical analysis of third-harmonic generation in a semiconductor slab is presented which allows the extraction of the electronic third-order susceptibility from the experiments. A simple method was used for the elimination of environmental effects on the measurements. The third-order susceptibilities obtained are {}χₓₓₓₓ⁽³⁾({ω},{ω},{ω}) _λ=1.0640ex0exμm=(9±{}4) ×{}10^-9 esu and {}χₓₓₓₓ⁽³⁾({ω},{ω},{ω}) _λ=1.9070ex0exμm =(1.7±{}0.7)×{}10^-8 esu, representing exceptionally high values compared to other organic and inorganic semiconductors.