title: Variable-focus liquid microlenses with adjustable 3-D curved housings.
abstract: This paper reports two novel types of variable-focus liquid microlenses with adjustable sensitivity, which consist of a poly(dimethylsiloxane) (PDMS) lens housing with circular sidewall and a liquid with tunable volume stored in it. The type-I lens housing ("in" bridge structure) is molded from water droplet sandwiched between two plates with identical wettability and the type-II lens housing ("out" bridge structure) is molded from solid microsphere. Because of the variable slope of the sidewall, the altitude of the liquid/air interface, which can be regulated by hydrostatic pressure, determines the curvature of the meniscus and hence the focal length (f). The curvature radius of sidewall, which determines the sensitivity, depends on the surface wettability or the radius of solid microsphere, thus, it is adjustable. Both of the two types of lenses have wide dynamic range, and their tuning tendencies are opposite. The experimental demonstrations and theoretical simulations yield good agreement in the key aspects of the optics.
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Graduate School of the Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, People's Republic of China.
authors.forename: Benhui
authors.initials: B
authors.lastname: Hu
authors.forename: Longjian
authors.initials: L
authors.lastname: Xue
authors.forename: Ping
authors.initials: P
authors.lastname: Yang
authors.forename: Yanchun
authors.initials: Y
authors.lastname: Han