Pozhidaev Evgeny P, Kiselev Alexei D, Srivastava Abhishek Kumar, Chigrinov Vladimir G, Kwok Hoi-Sing, Minchenko Maxim V
P. N. Lebedev Physics Institute of Russian Academy of Sciences, Leninsky prospect 53, 119991 Moscow, Russia.
Phys Rev E Stat Nonlin Soft Matter Phys. 2013 May;87(5):052502. doi: 10.1103/PhysRevE.87.052502. Epub 2013 May 16.
We study both theoretically and experimentally the electro-optical properties of vertically aligned deformed helix ferroelectric liquid crystals (VADHFLC) with subwavelength pitch that are governed by the electrically induced optical biaxiality of the smectic helical structure. The key theoretical result is that the principal refractive indices of homogenized VADHFLC cells exhibit the quadratic nonlinearity and such behavior might be interpreted as an orientational Kerr effect caused by the electric-field-induced orientational distortions of the FLC helix. In our experiments, it has been observed that, for sufficiently weak electric fields, the magnitude of biaxiality is proportional to the square of electric field in good agreement with our theoretical results for the effective dielectric tensor of VADHFLCs. Under certain conditions, the 2π phase modulation of light, which is caused by one of the induced refractive indices, is observed without changes in ellipticity of incident light.
我们从理论和实验两方面研究了具有亚波长间距的垂直排列变形螺旋铁电液晶（VADHFLC）的电光特性，其受近晶螺旋结构的电致光学双轴性支配。关键的理论结果是，均匀化VADHFLC盒的主折射率呈现二次非线性，这种行为可解释为由电场诱导的FLC螺旋取向畸变引起的取向克尔效应。在我们的实验中，已观察到，对于足够弱的电场，双轴性的大小与电场平方成正比，这与我们关于VADHFLC有效介电张量的理论结果吻合良好。在某些条件下，观察到由其中一个诱导折射率引起的光的2π相位调制，而入射光的椭圆率不变。
