A large extinction ratio optical shutter has been demonstrated using electrowetting liquids. The device is based on switching between a liquid-liquid interface curvature that produces total internal reflection and one that does not. The interface radius of curvature can be tuned continuously from 9 mm at 0 V to -45 mm at 26 V. Extinction ratios from 55.8 to 66.5 dB were measured. The device shows promise for ultracold chip-scale atomic clocks.
Montoya, Ryan D; Underwood, Kenneth; Terrab, Soraya; Watson, Alexander M; Bright, Victor M; and Gopinath, Juliet T, "Large extinction ratio optical electrowetting shutter." (2016). Mechanical Engineering Faculty Contributions. 20.