An optical system includes a light source, a film positioned to be illuminated by light from the light source, the film including a plurality of Bragg gratings configured to redirect the light, and an actuator configured to apply a shearing force to the film. The shearing force manipulates an orientation of the plurality of Bragg gratings to change an extent to which the plurality of Bragg gratings redirects the light and to thereby re-position a pupil at which the light converges after redirection by the plurality of Bragg gratings.