A Liquid Optical Phase Shifter With an Embedded Electrowetting Actuator

Abstract

We demonstrate an electrowetting-based liquid optical phase shifter. The phase shifter consists of two immiscible liquid layers with different refractive indices. Sandwiched between the two liquids is a rigid membrane that moves freely along the optical axis and supported by a compliant surround. When applied with a pressure, the thicknesses of both liquid layers change, which induces a difference in optical path, resulting in a phase shift. A miniaturized electrowetting-based actuator is used to produce hydraulic pressure. A multi-layered SU8 bonded structure was fabricated. A phase shift of 171° was observed when the device was incorporated in a Mach-Zehnder interferometer and driven with 100 V.

Dielectrowetting actuation of droplet: Theory and experimental validation*

“…Microfluidic controlling technology plays a critical role in micro-total analysis systems or lab-on-a-chip systems. [1][2][3] The controllable adjustment of the microfluidic can be realized by various methods, including thermal, [4] mechanical force, [5] dielectrowetting, [6][7][8] electrowetting, [9][10][11][12][13][14][15][16][17][18][19] and so on. Electrowetting technology has been found numerous potential applications in prism, [11,12] liquid lens, [13] displays, [14] labon-a-chip, [15] and light valve.…”