Digitally Tunable Microfluidic Optical Fiber Devices

Cattaneo, Francesco; Baldwin, K. W.; Yang, Shu; Krupenkine, T.; Ramachandran, Siddharth; Rogers, John A.

doi:10.1109/jmems.2003.820285

Cited by 37 publications

(31 citation statements)

References 8 publications

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“…The equations for the pressure field are (13) (14) where is the Laplacian operator, denotes the domain of the liquid droplet in two dimensions, is its boundary, is the pressure, is a chosen length scale, is the channel height, and is the curvature in the -plane. The curvature, , is given by (15) where and are the contact angles on the top and bottom of the EWOD device, respectively.…”

Section: Final Equation Summarymentioning

confidence: 99%

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Modeling the Fluid Dynamics of Electrowetting on Dielectric (EWOD)

Walker

Shapiro

2006

J. Microelectromech. Syst.

137

118

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Abstract-This paper discusses the modeling and simulation of a parallel-plate Electrowetting On Dielectric (EWOD) device that moves fluid droplets through surface tension effects. We model the fluid dynamics by using Hele-Shaw type equations with a focus on including the relevant boundary phenomena. Specifically, we show that contact angle saturation and hysteresis are needed to predict the correct shape and time scale of droplet motion. We demonstrate this by comparing our simulation to experimental data for a splitting droplet. Without these boundary effects, the simulation shows the droplet splitting into three pieces instead of two and the motion is over 15 times faster than the experiment. We then show how including the saturation characteristics of the device, and a simple model of contact angle hysteresis, allows the simulation to better predict the splitting experiment. The match is not perfect and suffers mainly because contact line pinning is not included. This is followed by a comparison between our simulation, whose parameters are now frozen, and a new experiment involving bulk droplet motion. Our numerical implementation uses the level set method, is fast, and is being used to design algorithms for the precise control of microdroplet motion, mixing, and splitting.[1439]

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Section: Final Equation Summarymentioning

confidence: 99%

“…Applications for these devices range from microfluid transport [9], mixing [10], dispensing [11], and "lab-on-a-chip" devices that automate functions like sensing and testing of biological samples [12], [13] to tunable optical fiber devices [14], [15] and reflective displays [16].…”

Section: Introductionmentioning

confidence: 99%

Modeling the Fluid Dynamics of Electrowetting on Dielectric (EWOD)

Walker

Shapiro

2006

J. Microelectromech. Syst.

137

118

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“…Similar strategy has been tested by us previously to independently pump multiple microfluidic plugs into or out of overlap with an optical fiber, allowing for a variety of different configurations to modulate the fiber transmission. [25] In a separate effort, we have fabricated soft lenses from hydrogels, which could change the shape, volume and refractive index continuously in response to external stimuli (pH, temperature, etc. ).…”

Section: Variable Transmission Using Dye-containing Solutionsmentioning

confidence: 99%

Tunable microfluidic optical devices with an integrated microlens array

Hong¹,

Wang²,

Sharonov³

et al. 2006

J. Micromech. Microeng.

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The interest in dynamically tuning light has attracted great attention to the fabrication of tunable microlens arrays. Here we discuss the fabrication and characterization of a simple, robust, yet tunable microfluidic optical device with integrated microlens array. The microfuidic device with desired channel structure was micromachined on a polycarbonate plate with a resolution up to 100 µm, followed by thermal bonding two plates above their glass transition temperature. The microlens arrays were replica molded on a glass slide, which was then attached to the polycarbonate plates. By simply actuating the liquids with variable refractive index into the fluidic channel to immerse the lens arrays without moving or deformation of microlenses, a large change of focal length of more than 10 times (ƒ=0.74 to 8.53) was achieved. When a dye-containing liquid was pumped into the microfluidic channel to cover the lenses, the light transmission through the lenses was reduced from about 95% to 55% when the dye concentration was increased to 10 w/v %. The knowledge we gain from these studies will provide important insights to contruct new, adaptive, micro-scale optical devices with multiple functionalities. 2 AbstractThe interest in dynamically tuning light has attracted great attention to the fabrication of tunable microlens arrays. Here we discuss the fabrication and characterization of a simple, robust, yet tunable microfluidic optical device with integrated microlens array. The microfluidic device with desired channel structure was micromachined on a polycarbonate plate with a resolution up to 100 μm, followed by thermal bonding two plates above their glass transition temperature. The microlens arrays were replica molded on a glass slide, which was then attached to the polycarbonate plates. By simply actuating the liquids with variable refractive index into the fluidic channel to immerse the lens arrays without moving or deformation of microlenses, a large change of focal length of more than 10 times (f = 0.74 to 8.53) was achieved. When a dye-containing liquid was pumped into the microfluidic channel to cover the lenses, the light transmission through the lenses was reduced from about 95% to 55% when the dye concentration was increased to 10 w/v %. The knowledge we gain from these studies will provide important insights to construct new, adaptive, micro-scale optical devices with multiple functionalities.

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“…To avoid electrolysis, an insulating layer is usually inserted between the droplet and electrodes [4]- [6]. The applications of EWOD devices were discussed extensively in the literature, including microfluid transport [7], tunable optical fiber devices [8], rotating liquid micromotor [9], micro-injection [10], particle separation and concentration control [11]. Other studies focusing on the modeling of EWOD devices can be found in [3,5,[12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation for a Droplet Fission Process of Electrowetting on Dielectric Device

Huang

Tan

2010

CICP

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Electrowetting has been proposed as a technique for manipulating droplets surrounded by air or oil. In this paper, we discuss the modeling and simulation of the droplet fission process between two parallel plates inside an electrowetting on dielectric (EWOD) device. Since the gap between the plates is small, we use the two-phase Hele-Shaw flow as a model. An immersed boundary (IB) method is employed to solve the governing equations and a local level set method is used to track the drop interface. For comparison purposes, the same set of two-phase HeleShaw equations are also solved directly using the ghost-fluid (GF) method. Numerical results are consistent with experimental observations reported in the literature, provided that care is taken to treat the contact angle.

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Digitally Tunable Microfluidic Optical Fiber Devices

Cited by 37 publications

References 8 publications

Modeling the Fluid Dynamics of Electrowetting on Dielectric (EWOD)

Modeling the Fluid Dynamics of Electrowetting on Dielectric (EWOD)

Tunable microfluidic optical devices with an integrated microlens array

Numerical Simulation for a Droplet Fission Process of Electrowetting on Dielectric Device

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