Liquid deformable mirror targets wavefront correction

Unlike conventional deformable mirrors that rely on the deformation of a thin plate or a membrane as a result of various actuation mechanisms (electrostatic, electromagnetic, or piezoelectric), a novel liquid deformable mirror based on electrocapillary actuation of liquid inside a microchannel array has been developed by researchers at Delft University of Technology (Delft, The Netherlands); the actuation principal has been validated with a test device.

Jul 1st, 2006

Unlike conventional deformable mirrors that rely on the deformation of a thin plate or a membrane as a result of various actuation mechanisms (electrostatic, electromagnetic, or piezoelectric), a novel liquid deformable mirror based on electrocapillary actuation of liquid inside a microchannel array has been developed by researchers at Delft University of Technology (Delft, The Netherlands); the actuation principal has been validated with a test device. The mirror could offer several advantages for adaptive-optics applications, including low power dissipation, fast response time, and low cost-although it is limited by its orientation.

Consisting of a vertically oriented microchannel array filled with two immiscible liquids (an aqueous electrolyte and a viscous dielectric liquid) and topped with a reflective membrane, the cylindrical capacitor design uses changing electrocapillary pressure to produce an upward or downward flow of liquid within the microchannels. This flow or push-pull deformation could be tuned to correct an aberrated wavefront. In the 64 x 64 hexagonally packed microchannel device tested (without a reflective layer), a response time corresponding to an operating frequency of 500 Hz was achieved for the deformations. Measurement of the rise time of the liquid surface indicates that maximum signal is reached after around 7 ms, corresponding to a surface displacement of about 1 mm. Numerical modeling of the proposed liquid-deformable-mirror concept and further measurements using the prototype are in progress. Contact Edgar Vuelban at e.vuelban@tnw.tudelft.nl.

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