ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
This paper presents a precise study of second-order optical nonlinearity of uniaxially cold-drawn and poled ferroelectric Nylon 11 films. The effects of drawing and poling on refractive indices and second-order nonlinear optical coefficients have been investigated. Drawing caused increase of refractive index (n) parallel to the drawing direction nX, and decrease of n perpendicular to drawing direction in the plane of film nY, as well as decrease of n on the poling direction parallel to film thickness direction nZ. Poling caused significant increase of nZ and decrease of nY. These n results imply that poling aligns the molecular chains so that carbonyl groups in Nylon backbone orient in the poling direction (Z-axis). Cold-drawn and poled Nylon 11 films belong to the mm2 point group. Dependence of second-order harmonic generation (SHG) intensity on incidence angle, i.e., Maker fringe pattern, could be precisely fitted using five independent nonzero tensor components, d33, d32, d31, d15, and d24. However, Kleinman symmetry was not satisfied: d31≠d15 and d32≠d24. The tensor components d33, d31, d15, and d24 increase with increasing remanent polarization, whereas the value of d32 was negligibly small irrespective of the intensity of the remanent polarization. Tensor components of microscopic first-order hyperpolarizability, βzxx, βzyy, βzzz, βxxz, and βyyz were determined. Tensor component βzzz was the largest and βzxx had negative sign. Second-order nonlinearity was largely suppressed in the vicinity of the melting point of Nylon 11. © 1998 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.476422
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