用于二阶非线性光学的横向偶氮桥联 H 型铁电介晶：铁电性和二次谐波产生。

Laterally azo-bridged h-shaped ferroelectric dimesogens for second-order nonlinear optics: ferroelectricity and second harmonic generation.

机构信息

Displaytech Inc., 2602 Clover Basin Drive, Longmont, Colorado 80503, USA.

出版信息

J Am Chem Soc. 2009 Dec 30;131(51):18386-92. doi: 10.1021/ja9069166.

PMID:19928850

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.

摘要

两类横向偶氮桥接 H 型铁电液晶（FLC），在 FLC 极轴上沿引入偶氮苯和分散红 1（DR-1）发色团，通过偏光显微镜、差示扫描量热法、二维 X 射线衍射分析和电光研究进行了合成和表征。它们代表了第一类展示基态、热力学稳定的反铁电向列相*（SmC*）的 H 型 FLC 材料，即基态铁电性。在入射波长为 1064nm 时，对一个含有 DR-1 发色团的化合物进行二次谐波产生测量，得到非线性系数 d(22) = 17 pm/V，这是迄今为止报道的棒状 FLC 中最大的非线性光学系数。该值使 FLC 在非线性光学中的应用成为可能。