Design, syntheses, and characterization of novel organic chromophores and polymers for electro-optic applications

This dissertation involves the design, synthesis and characterization of second order nonlinear optical chromophores and polymers for electro-optic modulator applications. Chapter 1 gives a brief introduction to nonlinear optics, electro-optic modulation and the requirements for device viable electro-optic polymeric materials. Chapter 2 presents the design, synthesis, and characterization of novel substituted dicyanomethylendihydrofuran-based high-{dollar}mubeta{dollar} NLO chromophores and their polymers. A second order NLO chromophore (FTC) exhibiting high molecular nonlinearity, high thermal stability, and low optical absorption has been synthesized and fully characterized. Exceptionally high electro-optic coefficients (residue value of 56.8 pm/V @ 1.06 {dollar}mu{dollar}m, maximum achievable value of 83 pm/V @ 1.3 {dollar}mu{dollar}m for FTC/PMMA) and low propagation optical losses (0.75 dB/cm for FTC/PMMA and 2.0 dB/cm for PU-FTC @ 1.3 {dollar}mu{dollar}m) have been achieved. Bias-poled modulators and high-speed electro-optic modulators have been fabricated using these materials. These extraordinary results make FTC-based EO materials the most promising materials for future device application at 1.3 and 1.55 microns. Chapter 3 involves the synthesis and evaluation of 4- (5- (4-N,N-(dialkylamino)phenyl) -penta-2,4-dien-1-diyl) -5-phenyl-3-isoxazolone-based PMMA composites and thermoset polyurethanes for electro-optic modulator applications. High electro-optic coefficient (49 pm/V @ 1.06 {dollar}mu{dollar}m) and low optical absorption {dollar}rm(lambdasb{lcub}max{rcub}=569{dollar} nm) were demonstrated with these materials PU-APTEI-DL and PU-APTEI-TL was synthesized and an electro-optic coefficient of 32 pm/V (DL) and reasonably good thermal stability (80{dollar}spcirc{dollar}C for DL; 110{dollar}spcirc{dollar}C for TL) was achieved for these crosslinked thermosetting polyurethane networks. Chapter 4 involves the synthesis and properties of a new perfluoroalkyldicyanovinyl-based NLO chromophore. Chapter 5 presents a theoretical analysis of the electrostatic interaction between chromophores with anisotropy of shape and local electrostatic field. The results demonstrated that the London-type interactions strongly dominate over dipole-alignment and Boltzman thermal randomization interactions the ordering of high-{dollar}mubeta{dollar} organic chromophores and has demonstrated excellent agreement between modified London theory (in which the shape of the chromophore and anisotropy of electrostatic properties were taken into account) and the experimental results.