Electrically actuated elastomers for electro-optical modulators

By using an elastomer as dielectric medium in a parallel plate capacitor, the attractive forces between the differently charged electrodes strongly compress that layer, representing a special type of electrostrictive effect. With an optical interference technique at the metal-insulator-metal layer system we studied the temporal behaviour of this mechanical deformation. We show that the deformation can be enhanced when the capacitor is laterally structured in order to allow the elastomer volume between the electrodes to move laterally, resulting in typical response times below 1 ms. The elastomer together with the metal electrodes is a metal-insulator-metal optical waveguide, whose mode properties can be tuned by electrically controlled mechanical thickness changes, suggesting applications for low-price electro-optical modulators with response speeds comparable to thermo-optical polymer modulators but with much smaller size.