Real time optical poling and third harmonic generation of Azo polymer thin films
碩士 === 國立中正大學 === 物理系 === 88 === Simultaneous writing and probing photoinduced second order susceptibility χ(2) in Azo-dye polymer thin film is demonstrated. The method is based on properties of χ(2) response providing different planes of polarization for seeding and signal second harmonics. Our tec...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2000
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| Online Access: | http://ndltd.ncl.edu.tw/handle/67235980730642748750 |
| Summary: | 碩士 === 國立中正大學 === 物理系 === 88 === Simultaneous writing and probing photoinduced second order susceptibility χ(2) in Azo-dye polymer thin film is demonstrated. The method is based on properties of χ(2) response providing different planes of polarization for seeding and signal second harmonics. Our technique allows to monitor the χ(2) value in real time excluding completely distortion of optical poling process, that can occur in traditional probing configurations. The possibility to attain high χ(2) in DR1-PMMA “guest-host” system under low seeding intensities is shown.
The possibility of control the third harmonic generation in polymethylmethacylate(PMMA) doped with disperse red 1(DR1) via exposition by frequency doubled and fundamental radiation of Nd:YAG laser is demonstrated. It turned out possible to change the third harmonic efficiency up to 4 times depending on pumping intensity. The change was completely reversible after 20 minutes of dark relaxation in the case of pumping the sample with the second harmonic, This effect is attributed to reversible change of third order susceptibility due to trans-to-cis isomerization of Azo-bond molecules.
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