Optical apparatus includes an electrically-tunable lens, including an electro-optical layer, having, for a given polarization of light incident on the layer, an effective local index of refraction at any given location within an active area of the electro-optical layer that is determined by a voltage waveform applied across the electro-optical layer at the location. Conductive electrodes extend over opposing first and second sides of the electro-optical layer and include an array of excitation electrodes. Control circuitry applies control voltage waveforms to the excitation electrodes. A polarization rotator is positioned and configured to intercept incoming light that is directed toward the lens and to rotate a polarization of the intercepted light so as to ensure that the light incident on the electro-optical layer has a component of the given polarization regardless of an initial linear polarization of the intercepted light.