A pH-tunable hydrogel microlens array with temperature-actuated light-switching capability

In this letter, we demonstrate a two step casting process to fabricate a bifunctional hydrogel-based microlens array, which responds to both temperature (becomes opaque above certain temperature) and pH (changes its focal length at different pH levels), and can be operated in air for an extended period of time. Each lens in the array is 1 mm in diameter and its focal length changes from 4.5 to 55 mm when the environmental pH is varied between 2.0 and 5.0. The light-switching capability is measured to be ∼92% when temperature increases from 25 to 35 °C.

[1]  Graham T. Reed,et al.  Silicon optical modulators , 2005 .

[2]  De-Ying Zhang,et al.  Fluidic adaptive lens with high focal length tunability , 2003 .

[3]  R. Rosenfeld.  Nature , 2009, Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery.

[4]  Pietro Ferraro,et al.  Liquid micro-lens array activated by selective electrowetting on lithium niobate substrates. , 2008, Optics express.

[5]  S. Kuiper,et al.  Variable-focus liquid lens for miniature cameras , 2004 .

[6]  Keiji Nagai,et al.  Thermal responsive microlens arrays , 2006 .

[7]  A. K. Agarwal,et al.  Adaptive liquid microlenses activated by stimuli-responsive hydrogels , 2006, Nature.

[8]  Zhongze Gu,et al.  Liquid microlens with tunable focal length and light transmission , 2008 .

[9]  Luke P. Lee,et al.  Tunable liquid-filled microlens array integrated with microfluidic network. , 2003, Optics express.

[10]  Jing Wang,et al.  Tunable microfluidic optical devices with an integrated microlens array , 2006 .

[11]  Mangilal Agarwal,et al.  Polymer-based variable focal length microlens system , 2004 .

[12]  Aa Anton Darhuber,et al.  PRINCIPLES OF MICROFLUIDIC ACTUATION BY MODULATION OF SURFACE STRESSES , 2005 .

[13]  Chau Fook Siong,et al.  A tunable Shack–Hartmann wavefront sensor based on a liquid-filled microlens array , 2008 .

[14]  R. Feynman,et al.  The Feynman Lectures on Physics Addison-Wesley Reading , 1963 .

[15]  S. Kuiper,et al.  Through a lens sharply [FluidFocus lens] , 2004, IEEE Spectrum.

[16]  F. Tseng,et al.  Electrostatic-Force-Modulated Microaspherical Lens for Optical Pickup Head , 2008, Journal of Microelectromechanical Systems.

[17]  IEEE Spectrum , 2022 .

[18]  Weisong Wang,et al.  Variable-focusing microlens with microfluidic chip , 2004 .