Description
In the absence of external forces, liquid spontaneously assume a spherical cap shape if their edge is either free to move or pinned along the rim of a circular aperture. The curvature of the surface and hence refractive power of the resulting lens are governed by the pressure drop across the liquid surface. By controlling either the pressure drop or the diameter of the aperture (e.g. by tuning the contact angle of using electrowetting), spherical liquid lenses of variable focal length can be realized. Non-spherical tunable drop shapes can either be achieved indirectly by applying non-symmetric boundary conditions along the edge of the droplets or directly by applying additional electrical forces that distort the liquid surface and in a controlled manner. I will present an overview of developments based on the latter approach. By applying variable voltages to segmented electrodes, the distribution of the electric field can be controlled. The equilibrium between the local electric stresses and the capillary pressure across the liquid surface gives rise to surface shapes that allow to vary the strength of low order aberrations (spherical, cylinder, coma) over a wide range, as evidenced by numerical simulations in combination with wavefront measurements using a Shack-Hartmann sensor. Optimization of electrode geometry and careful control of liquid-liquid interfacial tensions provide a potential for flexible aberration correction in various applications.| Period | 26 Jul 2021 |
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| Event title | Applied Industrial Optics 2021 |
| Event type | Conference |
| Location | Washington, United States, District of ColumbiaShow on map |