Tunable microlens actuated via a thermoelectrically driven liquid heat engine
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چکیده
Articles you may be interested in Thermally actuated tunable liquid microlens with sub-second response time Appl. A versatile liquid-core/liquid-twin-cladding waveguide micro flow cell fabricated by rapid prototyping Appl. A p H-tunable hydrogel microlens array with temperature-actuated light-switching capability Appl. We have developed a thermally actuated liquid microlens. An embedded thermoelectric element is used to actuate the liquid based heat engine. A closed-loop system is harnessed to drive and stabilize the temperature of the heat engine. Direct contact between the thermoelectric device and the water results in greatly improved, sub-second thermal rise time (0.8 s). The water based heat engine reacts to the variation in the temperature via expansion and contraction. In turn, the shape of a pinned water-oil meniscus at a lens aperture is deformed in response to the net volume change in the water, creating a tunable microlens. A method to fabricate microfluidic devices with relatively high thickness (250–750 lm) and large length-to-depth aspect ratio (280:1) was developed and used in the process. After fabrication and thermal calibration, optical characteristic of the microlens was assessed. Back focal length of the microlens was shown to vary continuously from À19.6 mm to À6.5 mm as the temperature increased from 5 C to 35 C. A thin film air was further introduced to insulate the heat engine from the substrate to protect the microlens area from the temperature fluctuation of the heat engine, thus preventing the change of the refractive indices and thermally induced aberrations. Wavefront aberration measurement was conducted. Surface profile of the microlens was mapped and found to have a conical shape. Both 3-dimensional and 1-dimensional thermal models for the device structure were developed and thermal simulation of the device was performed.
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تاریخ انتشار 2014