title: Tunable self-imaging effect using hybrid optofluidic waveguides.
abstract: Multimode interference (MMI) is a typical self-imaging phenomenon and has been widely exploited for optical devices like couplers and splitters. Usually, it utilizes solid waveguides only and thus has very limited tunability in self-imaging properties. This paper reports our original work on tunable MMI using a hybrid optofluidic waveguide. It is generated by the diffusion between miscible flows in a microchannel and consists of two parts: gradient-index liquid-liquid waveguide for light modulation and step-index liquid-solid waveguide for image formation. Simulation and experiments have shown successful realization of the real-time tuning of self-imaging properties. For detail, the image point (focal spot) width could be modulated from 7 μm to 16 μm, and the self-imaging period changes in the range of 500 μm by varying the fluid properties. It is foreseeable that such a hybrid optofluidic waveguide may find wider applications in lab-on-a-chip systems and optical devices.
authors.affiliation: School of Physics & Technology, Wuhan University, Wuhan 430072, China. yangyiys@whu.edu.cn.
authors.forename: Y
authors.initials: Y
authors.lastname: Shi
authors.affiliation: School of Physics & Technology, Wuhan University, Wuhan 430072, China. yangyiys@whu.edu.cn.
authors.forename: L
authors.initials: L
authors.lastname: Liang
authors.affiliation: School of Physics & Technology, Wuhan University, Wuhan 430072, China. yangyiys@whu.edu.cn.
authors.forename: X Q
authors.initials: XQ
authors.lastname: Zhu
authors.affiliation: Department of Applied Physics, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
authors.forename: X M
authors.initials: XM
authors.lastname: Zhang
authors.affiliation: School of Physics & Technology, Wuhan University, Wuhan 430072, China. yangyiys@whu.edu.cn.
authors.forename: Y
authors.initials: Y
authors.lastname: Yang