1 December 1997 Two-photon absorption measured in the presence of strong one-photon saturation in cumulene-containing polymer
Author Affiliations +
The Z-scan technique is used to extract the real and imaginary third order nonlinear susceptibilities, Re(chi )(3) and Im(chi )(3), respectively. A series of Z scans were conducted at 590 nm (near one-photon resonance) on a cumulene-containing polymer, poly(p- phenylene-1,4-diphenyl-1,2,3-butatriene) or PPC3, prepared in solution. At very high peak focal point intensities two- photon absorption is seen superimposed on a one-photon saturation signature in open aperture Z scans. A negative real third-order nonlinear susceptibility is also observed in closed aperture Z scans. We describe a procedure to extract the desired third-order nonlinear susceptibilities by conducting Z scans at various peak focal point intensities and then fitting the results by adjusting Re(chi )(3) and saturation intensity. Molecular second hyperpolarizability, is calculated to be (-1.4 + 2.2i) X 10-29 esu which is almost 40 times larger than that measured in a monomer equivalent, and scaling nonlinearly with chain length. Z scans were also conducted at 780 nm, (below one-photon resonance) on PPC3 and also gives a molecular second hyperpolarizability that is greater than that seen in the monomer. The higher value of molecular second hyperpolarizability measured near one-photon resonance is attributed to the existence of a real state at the first transition in a two-photon process.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ron K. Meyer, Maxim N. Shkunov, Robert E. Benner, Werner Gellermann, Z. Valy Vardeny, Jesse Lin, Thomas J. Barton, "Two-photon absorption measured in the presence of strong one-photon saturation in cumulene-containing polymer", Proc. SPIE 3145, Optical Probes of Conjugated Polymers, (1 December 1997); doi: 10.1117/12.279297; https://doi.org/10.1117/12.279297

Back to Top