We report the observation of second harmonic generation in a new class of organic polymeric materials, namely, electric field poled polymer glasses. Both the observed second harmonic coefficient (d33=6.0±1.3×10−9 esu, at 1.58 μm wavelength) and the poling process are described by a thermodynamic model that we have developed. The ability to form thin films from these materials may qualify them for integrated optics applications.
Electro-optic phase modulation was measured along with optical second-harmonic generation in thin films of a new copolymer containing a dicyanovinyl-terminated azo dye side chain. Orientational order was imparted to these films by poling with a corona discharge. Details of the electro-optic measurement technique, in which the real part of the electro-optic coefficient can be determined directly, are presented. Taking advantage of the increased orientation imparted by corona poling and the hindered motion of the nonlinear optical moiety in the side chain of the polymer leads to substantial improvements in both the magnitude and stability of nonlinear optical susceptibilities compared to guest-host polymer systems ordered by electrode poling.
A new class of organic quinoid systems possessing intrinsically large, nonlinear second-order optical susceptibilities has been developed based on theoretical calculations and dc-induced second-harmonic generation measurements of the molecular second-order optical susceptibilities β. For one example, 2-(4-dicyanomethylenecyclohexa-2, 5-dienylidine)-imidazolidine (DCNQI), βx = −240±60×10−30 cm5/esu. The unusually large magnitude and sign originate from certain charge-correlated features in the quinoid ground and excited states.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.