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CHAPTER 3
Optical Components
Based on Dynamic
Liquid-Liquid
Interfaces
Sindy K. Y. Tang and George M. Whitesides
Department of Chemistry and Chemical Biology, Harvard University, Cambridge,
Massachusetts
3-1 Introduction
This chapter describes optical components based on dynamic liquid-
liquid (L ) interfaces between liquids with different optical properties
2
(such as index of refraction) in microfluidic systems. Devices with
optical interfaces formed by liquids have characteristics that are quite
different from solid-gas and solid-liquid systems commonly used in
conventional optics.
L systems have four attractive characteristics:
2
1. It is simple to reconfigure the properties and functions of L 2
systems in real time by adjusting the compositions of the liq-
uids, and their rates of flow.
2. Unlike their solid-state counterparts, polishing or high-
precision microfabrication is not necessary to obtain smooth
2
optical interfaces for L devices: the L interfaces are intrinsi-
2
cally smooth as a result of laminar flow that is characteristic
of microfluidic systems.
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