Synthesis and characterization of polymethyl methacrylate with double electro-optic molecules thin film and its application

•Polymethyl methacrylate with double electro-optic molecules was synthesized.•Effect on EO coefficient of different 6OCB mixing proportions was investigated.•The polymer material showed enhanced EO coefficient and fine stability.•Thin films formed by this kind of material were used to detect THz radiation.•The detecting efficiency and the spectrum sensitivity are enhanced largely.

Polymethyl methacrylate (PMMA) with double electro-optic (EO) molecules was synthesized. One kind of chromophoric groups, hydroxyethyl carbazole, reacted with PMMA by a chemical method to form poly(methacrylic acid ethyl carbazole ester). Another small nonlinear optical molecule (NOL), 4–6-alkoxy-4′-cyano-biphenyl (6OCB), was mixed into the polymers by a physical method to further improve EO properties. The structure of the material was characterized and the effect on EO coefficient of different mixing proportions was investigated. Photoconductive properties and the orientation stability were studied. Experimental results showed that the enhanced EO coefficient was 44.8 pm/V when the mixing proportion was 20 wt%. Thermally stimulated discharge current (TSDC) testing curves were obtained, which confirmed the existence of two depolarization processes. Thin films formed by this polymer material were used to detect terahertz (THz) radiation. The detecting efficiency and the spectrum sensitivity were enhanced largely compared with ZnTe crystal. It can be concluded that this polymer material is a very good candidate for THz application.