Abstract:Results are presented of the properties of a liquid crystal wavefront corrector for adaptive optics. The device is controlled using modal addressing in which case the device behaves more like a continuous facesheet deformable mirror than a segmented one. Furthermore, the width and shape of the influence functions are electrically controllable. We describe the construction of the device, the optical properties, and we show experimental results of low order aberration generation.

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Mechanical properties of electrorheological suspensions are studied with computer simulations using a point-dipole model. The behaviour of these fluids is compared under constant-rate compressive and shear straining. The mechanisms of local deformations in single chains under straining are discussed. Also structures which have been grown before straining under the influence of electric field have been studied. In these structures the ratios of compression and shearing were found to have a significant effect on the corresponding yield stresses. The tensile yield stress was found to be about an order of magnitude larger than the sheared yield stress.