Adaptive optical beam steering and tuning system based on electrowetting driven fluidic rotor

Abstract

Reconfigurable beam steering components are indispensable to support optical and photonic network systems operating with high adaptability and with various functions. Currently, almost all such components are made of solid parts whose structures are rigid, and hence their functions are difficult to be reconfigured. Also, optical concentration beam steering is still a very challenging problem compared to radio frequency/microwave steering. Here we show a watermill-like beam steering system that can adaptively guide concentrating optical beam to targeted receivers. The system comprises a liquid droplet actuation mechanism based on electrowetting-on-dielectric, a superlattice-structured rotation hub, and an enhanced optical reflecting membrane. The specular reflector can be adaptively tuned within the lateral orientation of 360°, and the steering speed can reach~353.5°s −1 . This work demonstrates the feasibility of driving a macro-size solid structure with liquid microdroplets, opening a new avenue for developing reconfigurable components such as optical switches in next-generation sensor networks.

Electrowetting-on-dielectric (EWOD): Current perspectives and applications in ensuring food safety

“…The operation of the EWOD device relies on the application of the electric potential to change the wetting properties of the hydrophobic layer, resulting in a change in the contact angle and therefore actuating the droplet. Fluoropolymers such as Cytop are the most commonly used hydrophobic material for developing EWOD devices for both open and closed configurations [ 87 ]. In addition, other polymers, such as Teflon and Pluronics, have been explored due to their excellent hydrophobic properties by simply spin-coating a layer of a few nanometres thick [ 87 ].…”

“…Fluoropolymers such as Cytop are the most commonly used hydrophobic material for developing EWOD devices for both open and closed configurations [ 87 ]. In addition, other polymers, such as Teflon and Pluronics, have been explored due to their excellent hydrophobic properties by simply spin-coating a layer of a few nanometres thick [ 87 ]. Various studies have demonstrated that the surface roughness of the hydrophobic layer is crucial for determining the actuation voltage [ 55 ].…”

Influence of the Ground Electrode on the Dynamics of Electrowetting

“…Electrowetting is used in several applications, such as micro-drop generation, mixing and splitting [ 1 , 2 ], high-speed droplet actuation [ 3 , 4 ], chip cooling [ 5 ], drug release and clinical diagnosis [ 6 , 7 ], e-paper and electronic display [ 8 , 9 ], energy harvesting [ 10 ], solar indoor lighting [ 11 ], optics and beam steering [ 12 , 13 ]. In most electrowetting studies, the primary focus has been to observe the drop deformation and contact-angle change when the applied voltage is varied.…”

Evaporation-triggered directional transport of asymmetrically confined droplets

“…Correspondingly, the prescribed transport of the sample droplet towards the specific sensing spot before its complete evaporation is the prerequisite for the accurate screening of targeted analytes. During the past two decades, especially inspired by droplet motion on spider silk [11], cactus spines [12], and Cotula fallax plant [13], the directional transport of droplet has been realized through various strategies: (1) wettability gradient induced by surface textures [14], chemical functionalizations [15], thermal gradient [16] or electrowetting effect [17,18]; (2) external body forces including gravity [19], magnetic force [20] and electric force [21]; and (3) Laplace pressure difference due to the confinement in asymmetric geometries [11,[22][23][24][25][26][27][28]. However, the complex geometric structures, extra force/temperature/concentration fields, and functionalized surfaces with fragile micro/nanostructures involved in these technologies still restrict their practical applications.…”