Dynamic Liquid Optics

基于光流体的可调光学的力量源于能够控制地将液体界面变形为折射表面所需的形状。使用电润湿作为一种驱动技术，可调液体透镜、棱镜和扫描仪已经被证明，最近它甚至被证明可以产生具有可控光学像差的表面。许多这些发展的关键是使用具有高密度方位分布和单独寻址驱动电极的管状流体结构。然而，液体光学实现先进成像系统的能力还可以进一步扩展，DynaLO项目将尝试展示一种全新的方法，即通过透镜中的时变表面波来可控地生成任意液体表面轮廓。利用PI在先前工作中开发的32电极管状透镜的独特功能，将从理论上和实验上分析在透镜孔径上产生精确控制的行波和驻波的能力。DynaLO项目的灵感来自于可以在直径25米的波槽中使用机械致动器产生的波浪模式，该项目将把这一概念转化为一个5毫米的液体透镜。预计这种动态表面波可以用来产生各种各样的表面特征，也可以产生非圆对称的表面特征，这是静态驱动无法实现的。这种新颖的动态表面整形将与静态表面整形以及反馈稳定的界面定位相结合，以允许产生更大范围的光学自由曲面。液体轮廓将被实时监测，并且由于透镜方向变化或系统振动而引起的界面变化将被直接补偿。最终目标将是一个液体透镜，其驱动可以瞬间和连续调整，以确保所需的轮廓产生。如果成功，动态表面波方法结合静态界面整形将为可调谐液体光学元件开辟全新的视野。

The power of tunable optics based on optofluidics stems from the ability to controllably deform liquid interfaces to a desired shape for a refractive surface. Using electrowetting as an actuation technique, tunable liquid lenses, prisms, and scanners have been demonstrated, and recently it has even been shown that surfaces with controlled optical aberrations may be generated. Key to many of these developments has been the use of a tubular fluidic structure with a high density of azimuthally-distributed and individuallyaddressable actuation electrodes. Yet the capabilities of liquid optics for realizing advanced imaging systems can be extended further, and the DynaLO project will attempt to demonstrate an entirely new means for controllably generating arbitrary liquid surface profiles, namely through time-varying surface waves in the lens. With the unique capabilities of the 32-electrode tubular lenses developed by the PI in prior work, the ability to generate precisely-controlled traveling and standing waves across the lens aperture will be analyzed theoretically and experimentally. Inspired by the wave patterns which can be generated in 25 m diameter wave tanks using mechanical actuators, the DynaLO project will translate this concept to a 5 mm liquid lens. It is expected that such dynamic surface waves can be used to generate a wide variety of surface features, also non-circularly-symmetric ones, which cannot be achieved using static actuation. This novel dynamic surface shaping will then be combined with static surface shaping as well as feedback-stabilized interface positioning to allow the generation of an even wider range of optical freeform surfaces. The liquid profile will be monitored in real time and interface variations due to, for example, orientation changes of the lens or system vibrations, will be directly compensated. The ultimate goal will be a liquid lens for which actuation can be instantaneously and continuously adjusted to assure that the desired profile is generated. If successful, the dynamic surface wave approach combined with static interface shaping will open entirely new horizons for tunable liquid optical components.