An electronically dimmable optical device configured to act upon incident light having two orthogonal polarization directions, comprising: a viewing surface, on which the incident light falls, arranged closest to the viewer's eye formed by an active absorbing polarizer that is electrically switchable having an absorptive axis, followed by a first static reflective polarizer adjacent the active absorbing polarizer and having a first reflective axis, the first static reflective polarizer configured to reflect one of the two orthogonal polarization directions of the incident light that is parallel to said reflective axis more than the other polarization direction; followed by an active polarization rotator that is electrically switchable adjacent the first static reflective polarizer and capable of altering the polarization direction of the two orthogonal polarization directions by a value between 0 and 90° including both end values; and followed by a second static reflective polarizer adjacent the active polarization rotator and having a second reflective axis, configured to reflect the other of the two orthogonal polarization directions of the incident light that is parallel to said second reflective axis more than the one of the two orthogonal polarization directions; characterised in that the active absorbing polarizer in configured so that when activated it substantially absorbs a selected polarization of the incident light that is parallel to said absorptive axis, and when not activated it transmits light of either polarization direction, and in that the device is configured so that it has a maximum reflectivity when no voltage is applied to the active absorbing polarizer and active polarization rotator and a minimum reflectivity when a suitable voltage is applied to each of said active absorbing polarizer and active polarization rotator. a viewing surface, on which the incident light falls, arranged closest to the viewer's eye formed by an active absorbing polarizer that is electrically switchable having an absorptive axis, followed by a first static reflective polarizer adjacent the active absorbing polarizer and having a first reflective axis, the first static reflective polarizer configured to reflect one of the two orthogonal polarization directions of the incident light that is parallel to said reflective axis more than the other polarization direction; followed by an active polarization rotator that is electrically switchable adjacent the first static reflective polarizer and capable of altering the polarization direction of the two orthogonal polarization directions by a value between 0 and 90° including both end values; and followed by a second static reflective polarizer adjacent the active polarization rotator and having a second reflective axis, configured to reflect the other of the two orthogonal polarization directions of the incident light that is parallel to said second reflective axis more than the one of the two orthogonal polarization directions; characterised in that the active absorbing polarizer in configured so that when activated it substantially absorbs a selected polarization of the incident light that is parallel to said absorptive axis, and when not activated it transmits light of either polarization direction, and in that the device is configured so that it has a maximum reflectivity when no voltage is applied to the active absorbing polarizer and active polarization rotator and a minimum reflectivity when a suitable voltage is applied to each of said active absorbing polarizer and active polarization rotator.