Inducing variable pitch gratings in nematic liquid crystals using chirped surface acoustic wave transducers
Inducing variable pitch gratings in nematic liquid crystals using chirped surface acoustic wave transducers
复制标题
使用啁啾表面声波换能器在向列液晶中感应可变节距光栅
DOI：
10.1088/1361-6463/ac7013
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Morris R
中科院分区：
文献类型：
--
作者：
Morris R
在液晶中诱导流体动力学流动会改变指向矢的对称轴，从而引起光学性质的变化。所得光栅具有作为可切换衍射光学元件（DOE）的潜在用途。在这项研究中，表面声波（SAW）被施加到NLC设备，通过流体动力学不稳定性诱导周期性涡。我们表明，所施加的SAW的波长和诱导的光栅周期之间的线性关系，其中的系数是由在基板中的声音的速度在NLC的比率。利用这种关系设计了一种新型器件，该器件利用宽带（啁啾）声表面波换能器，可使流体动力学光栅的周期在90 μm ~ 260 μm范围内连续变化。这些器件为创建一类新的连续可变DOE提供了巨大的潜力，克服了当前的技术限制。
Inducing hydrodynamic flow in nematic liquid crystals (NLCs) reorients the symmetry axis of the material—the director, causing changes in the optical properties. The resulting optical gratings have potential use as switchable diffractive optical elements (DOEs). In this study, surface acoustic waves (SAWs) are applied to an NLC device to induce periodic vortices through hydrodynamic instabilities. We show a linear relationship between the wavelength of the applied SAW and induced grating period, where the coefficient is determined by the ratio of the speed of sound in the substrate to that in the NLC. This relationship is further used to design a novel device, where the period of the hydrodynamic grating can be continuously varied from 90 μm to 260 μm by utilizing a broadband (chirped) SAW transducer. These devices present great potential for creating a new class of continuously variable DOEs, overcoming current technological limitations.