Lee W, Chiu C S
Opt Lett. 2001 Apr 15;26(8):521-3. doi: 10.1364/ol.26.000521.
Diffraction gratings were studied in cells of the homogeneously aligned liquid-crystal E7 doped with multiwall carbon nanotubes. These phase gratings were induced by interference modulation of two coherent optical beams, in conjunction with an applied dc field that was perpendicular to the unperturbed director axis. Self-diffraction was observed at all angles of incidence of the writing beams, including normal incidence. A superior nonlinear-index coefficient of 5x10(-2)cm(2)/W was obtained after passage of a 44-mW/cm(2) beam through a film with a grating constant of 18 mum under an external voltage of 15 V. The observed phenomenon depends strongly on the applied dc field, and the memory effect in a nematic film depends strongly on the grating constant.
在掺杂多壁碳纳米管的均匀排列液晶E7的单元中研究了衍射光栅。这些相位光栅是由两束相干光束的干涉调制以及垂直于未受干扰的指向矢轴施加的直流电场共同诱导产生的。在写入光束的所有入射角（包括正入射）下均观察到了自衍射现象。在15V的外部电压下，一束44mW/cm²的光束通过光栅常数为18μm的薄膜后，获得了5×10⁻²cm²/W的优异非线性折射率系数。观察到的现象强烈依赖于所施加的直流电场，而向列相薄膜中的记忆效应则强烈依赖于光栅常数。
