Large extinction ratio optical electrowetting shutter.

Ryan D Montoya,Alexander M Watson,Juliet T Gopinath,Kenneth Underwood,Victor M Bright,Soraya Terrab

doi:10.1364/oe.24.009660

Abstract

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.

Highlights

High extinction ratio optical shutters are important for atomic clocks, gyroscopes, communications, lab-on-a-chip systems, and displays
The device is based on switching between a liquid-liquid interface curvature that produces total internal reflection and one that does not
Future designs may achieve even greater extinction by avoiding sidewall interaction as well as utilizing new geometries, and with future miniaturization show promise for high speed shutter applications in atomic physics, displays, communications and imaging

Summary

Introduction

High extinction ratio optical shutters are important for atomic clocks, gyroscopes, communications, lab-on-a-chip systems, and displays. Existing technologies include integrated lithium-niobate electro-optic modulators [1], acousto-optic modulators [2], and mechanical methods based on diaphragms or blades [3]. These systems provide elegant solutions for many applications. An attractive alternative for applications requiring large extinction ratio without mechanical parts is offered by liquid-based optical devices. There are previous demonstrations of electrowetting-based displays [9], tunable irises [10], and switches [11,12,13,14], high extinction ratio (beyond 30 dB) shutters have not been demonstrated. To the best of our knowledge, this is the largest extinction ratio demonstrated by an electrowettingbased total-internal-reflection device to date

Shutter design

Fabrication

Results

Conclusion