High-efficiency generation of harmonics in polythiophene
| Autor: | L. V. Kulik, D. A. Nevostruev, A. V. Ivanenko, B. N. Nyushkov, S. I. Trashkeev, V. M. Klement'ev, N. T. Vasenin, M. N. Khomyakov |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
business.industry Nonlinear optics Statistical and Nonlinear Physics Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials chemistry.chemical_compound chemistry Liquid crystal Harmonics Optoelectronics Polythiophene High harmonic generation Electrical and Electronic Engineering business |
| Zdroj: | Quantum Electronics. 51:437-445 |
| ISSN: | 1468-4799 1063-7818 |
| DOI: | 10.1070/qel17509 |
| Popis: | High-efficiency harmonic generation is observed in a semiconducting polymer RR-P3HT [regioregular poly(3-hexylthiophene)], which exhibits a high nonlinear susceptibility [χ (2) > 10−6 m V−1] under pumping by a pulsed fibre laser. The harmonic generation efficiency in RR-P3HT is comparable or higher than that observed for liquid crystals, which are used in reference experiments to estimate the susceptibility [the quadratic susceptibility of a nematic liquid crystal NLC 1289 is χ (2) ≈ 2 × 10−6 m V−1]. No generation is observed in polythiophene with a random structure, RRa-P3HT [regiorandom poly(3-hexylthiophene)], at the same pump power. It is experimentally demonstrated that a necessary condition for generating the second and third harmonics in a polymer, along with a high pump power density, is the presence of a large power density gradient (exceeding 1013 W m−3). Based on a preliminary theoretical analysis, we can suggest that the quadrupole mechanism, which is a consequence of the regularity of RR-P3HT structure in the thin near-wall layer, may contribute significantly to the nonlinear radiation conversion in semiconducting polymers. |
| Databáze: | OpenAIRE |
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