Nonlinear optical activities

J. L. Bredas and R. Silby, Conjugated Polymers The Novel Science and Technology of Highly Conducting and Nonlinear Optically Active Materials, Kluwer Academic, Boston, 1991. 

Nonlinear Optical Activity in Second-Harmonic Generation... 

Nonlinear Optical Activity and Magnetic Dipole Contributions... 

Comparison of Linearly and Circularly Polarized Probes of Nonlinear Optical Activity of Chiral Surfaces... 

Study of Biological Sample with Nonlinear Optical Activity... 

In the following sections we will first in Section 2 briefly discuss the necessary background to understand optical activity effects in linear and nonlinear optics and to illustrate the similarities and differences between both types. In Section 3 we present a more thorough analysis of nonlinear optical effects in second-harmonic generation, both from a theoretical and an experimental point of view. Section 4 deals with experimental examples that illustrate the usefulness of nonlinear optical activity in the study of chiral thin films and surfaces. Finally, in Section 5 we give an overview of the role of chirality in the field of second-order nonlinear optics and show that chiral molecules can be useful for applications in this field. 

ANALYSIS OF NONLINEAR OPTICAL ACTIVITY 3.1 Theoretical Formalism... 

The experimental geometry to study nonlinear optical activity in SHG from... 

It is important to note that the coefficients fp, gp, and hs are always nonvanishing, for both achiral and chiral isotropic films. On the other hand, fs, gs, and hp can only be nonvanishing if the isotropic film is chiral (nonracemic) because they completely depend on the chiral susceptibility components. Note that gs is always equal to zero within the electric dipole approximation. The sign of the chiral expansion coefficients changes between enantiomers, while that of the achiral expansion coefficients stays the same. Experimental determination of all expansion coefficients fully characterizes the nonlinearity and nonlinear optical activity of the sample. Once all expansion coefficients are... 

Voigt-Martin, I.G., Kothe, H., Yaminsky, A.V., Tenkovtsev, A.V., Zandbergen, H., Jansen, J. and Gilmore, C.J. (2000) Comparison of electron diffraction data from nonlinear optically active organic DMABC Crystals obtained at lOOkV and 300kV Ultramicroscopy, 83, 33-59. 

The poiygermanes exhibit many of the same electronic properties as polysilanes, including near-uv photoabsorpilon. thermochroniism. photo-bleaching. as well as nonlinear optical activity, and have seen a fair amount of theoretical and experimental investigation, However, despiie similarities with polysilanes, poiygermanes appear to he unlikely candidates for commercial exploitation,... 

A number of liquid crystalline polyphosphazenes with mesogenic side groups have been prepared (48—50). Polymers with nonlinear optical activity have also been reported (51). Polyphosphazene membranes have been examined for gas, liquid, and metal ion separation, and for filtration (52—54). There is interest in phosphazene—organic copolymers, blends, and interpenetrating polymer networks (IPNs) (55—61) to take advantage of some of the special characteristics of phosphazenes such as flame retardance and low temperature flexibility. A large number of organic polymers with cydophosphazene substituents have been made (62). 

SPANGLER AND HAVELKA Nonlinear Optic-Active Polymers... 

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