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Optical Science, Engineering and Instrumentation '97, 1997, San Diego, CA, United States, Ron K. Meyer, Martin Liess, Robert E. Benner, Werner Gellermann, Z. Valy Vardeny, Masanori Ozaki, Katsumi Yoshino, Yi Wei Ding, and Thomas J. Barton "Two-photon absorption spectra of luminescent conducting polymers measured over wide spectral range", Proc. SPIE 3145, Optical Probes of Conjugated Polymers, (1 December 1997). DOI: https://doi.org/10.1117/12.279279, We report the two-photon absorption (TPA) spectra of poly(2,5-dibutoxy-p-phenylene acetylene) (PPA-DBO), poly(2,5-dioctyloxy-p-phenylene vinylene) (PPV-DOO), and poly(3-hexylthiophene) in the spectral range extending from 576 nm to 846 nm. Using the Z-scan technique on the polymers in solution, we measured a strong two-photon allowed transition in all three materials which we attribute to the mAg essential state. In the case of PPA-DBO and PPV-DOO, TPA peaks were coincident with dispersion in the nonlinear refractive indices as detected by reduced aperture Z scan. In all three polymers this peak occurs at approximately 1.3 the bandgap energy. The excitonic nature of the excited electronic states in PPA-DBO is indicated by the lack of a TPA band at or near the 1Bu exciton position. Saturation was observed in the nonlinear index of refraction near spectral peaks, as well as an apparent reverse Kramers- Kronig effect.

Optical Science, Engineering and Instrumentation '97, 1997, San Diego, CA, United States, Sergey V. Frolov, Werner Gellermann, Z. Valy Vardeny, Masanori Ozaki, Katsumi Yoshino, Thomas J. Barton, and Guglielmo Lanzani "Near-infrared ps transient photoinduced absorption in conjugated systems", Proc. SPIE 3145, Optical Probes of Conjugated Polymers, (1 December 1997). DOI: https://doi.org/10.1117/12.295537, We demonstrate the use of a color center laser in a pump- and-probe correlation technique which enables us to extend the probe spectral range into the infrared. As a result, we find strong photoinduced infrared absorption in several (pi) -conjugated polymers and oligomers. We associate this absorption with optical transitions in the singlet exciton manifold.

Optical Science, Engineering and Instrumentation '97, 1997, San Diego, CA, United States, Jiandong D. Huang, Sergey V. Frolov, Z. Valy Vardeny, W. Chen, Thomas J. Barton, R. Sugimoto, Masanori Ozaki, and Katsumi Yoshino "Ultrafast femtosecond relaxation processes in luminescent and nonluminescent conducting polymers", Proc. SPIE 3145, Optical Probes of Conjugated Polymers, (1 December 1997). DOI: https://doi.org/10.1117/12.284153, We have employed the time-resolved photomodulation (PM) technique to study the photoexcitation dynamics of a luminescent (Si-PT) and nonluminescent (s-(CH)x) conducting polymers in the low signal limit. In each polymer, we identify two exponential decay processes in the PM decay, with characteristic time constants T1 and T2, where T1 is of order 1 ps and T2 depends on the specific polymer; T2 in Si-PT is about 50 ps, whereas T2 in s-(CH)x is about 5 ps. The difference in T2 is tentatively attributed to radiative and non-radiative recombination kinetics, respectively. We also found that the PM decay does not show any obvious temperature and intensity dependences, whereas the polarization memory decay is longer at low temperatures.

Optical Science, Engineering and Instrumentation '97, 1997, San Diego, CA, United States, Jiandong D. Huang, Sergey V. Frolov, Z. Valy Vardeny, W. Chen, Thomas J. Barton, R. Sugimoto, Masanori Ozaki, and Katsumi Yoshino "Ultrafast femtosecond relaxation processes in luminescent and nonluminescent conducting polymers", Proc. SPIE 3145, Optical Probes of Conjugated Polymers, (1 December 1997). DOI: https://doi.org/10.1117/12.284153, We have employed the time-resolved photomodulation (PM) technique to study the photoexcitation dynamics of a luminescent (Si-PT) and nonluminescent (s-(CH)x) conducting polymers in the low signal limit. In each polymer, we identify two exponential decay processes in the PM decay, with characteristic time constants T1 and T2, where T1 is of order 1 ps and T2 depends on the specific polymer; T2 in Si-PT is about 50 ps, whereas T2 in s-(CH)x is about 5 ps. The difference in T2 is tentatively attributed to radiative and non-radiative recombination kinetics, respectively. We also found that the PM decay does not show any obvious temperature and intensity dependences, whereas the polarization memory decay is longer at low temperatures.

Optical Science, Engineering and Instrumentation '97, 1997, San Diego, CA, United States, Sergey V. Frolov, Werner Gellermann, Z. Valy Vardeny, Masanori Ozaki, Katsumi Yoshino, Thomas J. Barton, and Guglielmo Lanzani "Near-infrared ps transient photoinduced absorption in conjugated systems", Proc. SPIE 3145, Optical Probes of Conjugated Polymers, (1 December 1997). DOI: https://doi.org/10.1117/12.295537, We demonstrate the use of a color center laser in a pump- and-probe correlation technique which enables us to extend the probe spectral range into the infrared. As a result, we find strong photoinduced infrared absorption in several (pi) -conjugated polymers and oligomers. We associate this absorption with optical transitions in the singlet exciton manifold.

Optical Science, Engineering and Instrumentation '97, 1997, San Diego, CA, United States, Ron K. Meyer, Martin Liess, Robert E. Benner, Werner Gellermann, Z. Valy Vardeny, Masanori Ozaki, Katsumi Yoshino, Yi Wei Ding, and Thomas J. Barton "Two-photon absorption spectra of luminescent conducting polymers measured over wide spectral range", Proc. SPIE 3145, Optical Probes of Conjugated Polymers, (1 December 1997). DOI: https://doi.org/10.1117/12.279279, We report the two-photon absorption (TPA) spectra of poly(2,5-dibutoxy-p-phenylene acetylene) (PPA-DBO), poly(2,5-dioctyloxy-p-phenylene vinylene) (PPV-DOO), and poly(3-hexylthiophene) in the spectral range extending from 576 nm to 846 nm. Using the Z-scan technique on the polymers in solution, we measured a strong two-photon allowed transition in all three materials which we attribute to the mAg essential state. In the case of PPA-DBO and PPV-DOO, TPA peaks were coincident with dispersion in the nonlinear refractive indices as detected by reduced aperture Z scan. In all three polymers this peak occurs at approximately 1.3 the bandgap energy. The excitonic nature of the excited electronic states in PPA-DBO is indicated by the lack of a TPA band at or near the 1Bu exciton position. Saturation was observed in the nonlinear index of refraction near spectral peaks, as well as an apparent reverse Kramers- Kronig effect.