You can do that 'continuously' by inserting many layers of slightly rotated polarizers to rotate the polarization plane by an arbitrary angle. An applied examp

You can do that 'continuously' by inserting many layers of slightly rotated polarizers to rotate the polarization plane by an arbitrary angle. An applied example of this are liquid crystal screens. Molecules take the role of the polarizers there. The rotation angle depends on an applied electric field and when you sandwich a layer of crystals between polarizers, you almost have a screen: https://www.britannica.com/technology/twisted-nematic-cell https://www.britannica.com/technology/twisted-nematic-cell