title: Laterally azo-bridged h-shaped ferroelectric dimesogens for second-order nonlinear optics: ferroelectricity and second harmonic generation.
abstract: Two classes of laterally azo-bridged H-shaped ferroelectric liquid crystals (FLCs), incorporating azobenzene and disperse red 1 (DR-1) chromophores along the FLC polar axes, were synthesized and characterized by polarized light microscopy, differential scanning calorimetry, 2D X-ray diffraction analysis, and electro-optical investigations. They represent the first H-shaped FLC materials exhibiting the ground-state, thermodynamically stable enantiotropic SmC* phase, i.e., ground-state ferroelectricity. Second harmonic generation measurements of one compound incorporating a DR-1 chromophore at the incident wavelength of 1064 nm give a nonlinear coefficient of d(22) = 17 pm/V, the largest nonlinear optics coefficient reported to date for calamitic FLCs. This value enables viable applications of FLCs in nonlinear optics.
authors.affiliation: Displaytech Inc., 2602 Clover Basin Drive, Longmont, Colorado 80503, USA. yqzhang@micron.com
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Josu
authors.initials: J
authors.lastname: Martinez-Perdiguero
authors.forename: Ute
authors.initials: U
authors.lastname: Baumeister
authors.forename: Christopher
authors.initials: C
authors.lastname: Walker
authors.forename: Jesus
authors.initials: J
authors.lastname: Etxebarria
authors.forename: Marko
authors.initials: M
authors.lastname: Prehm
authors.forename: Josu
authors.initials: J
authors.lastname: Ortega
authors.forename: Carsten
authors.initials: C
authors.lastname: Tschierske
authors.forename: Michael J
authors.initials: MJ
authors.lastname: O'Callaghan
authors.forename: Adam
authors.initials: A
authors.lastname: Harant
authors.forename: Mark
authors.initials: M
authors.lastname: Handschy