Voltage-programmable liquid optical interface


Recently, there has been intense interest in photonic devices based on microfluidics, including displays1,2 and refractive tunable microlenses and optical beamsteerers3,4,5 that work using the principle of electrowetting6,7. Here, we report a novel approach to optical devices in which static wrinkles are produced at the surface of a thin film of oil as a result of dielectrophoretic forces8,9,10. We have demonstrated this voltage-programmable surface wrinkling effect in periodic devices with pitch lengths of between 20 and 240 µm and with response times of less than 40 µs. By a careful choice of oils, it is possible to optimize either for high-amplitude sinusoidal wrinkles at micrometre-scale pitches or more complex non-sinusoidal profiles with higher Fourier components at longer pitches. This opens up the possibility of developing rapidly responsive voltage-programmable, polarization-insensitive transmission and reflection diffraction devices and arbitrary surface profile optical devices.

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Figure 1: Structure of the device.
Figure 2: Plot of the peak-to-peak amplitude A of the wrinkle at the oil–air interface and interferograms at different voltages.
Figure 3: Transient response of the intensity of the reflection mode first diffracted order as a function of time.
Figure 4: Intensity of the zero-, first- and second-order peaks due to the diffraction of light at 543 nm.
Figure 5: Profiles at a hexadecane oil–air interface that have been created by the action of a non-uniform electric field profile.


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The authors gratefully acknowledge J. Fyson at Kodak (European Research) Ltd and N. J. Shirtcliffe and C. L. Trabi at Nottingham Trent University for fruitful discussions. G.W. gratefully acknowledges The EPSRC/DTI COMIT Faraday Partnership and Kodak (European Research) Ltd for funding.

Author information

C.V.B., M.I.N. and G.M. conceived the concept and planning. C.V.B., G.G.W. and M.I.N. designed the experiment. C.V.B. and G.M. carried out theoretical work. C.V.B. wrote the paper and G.G.W. performed the experimental work and data analysis.

Correspondence to C. V. Brown.

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Brown, C., Wells, G., Newton, M. et al. Voltage-programmable liquid optical interface. Nature Photon 3, 403–405 (2009). https://doi.org/10.1038/nphoton.2009.99

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