1. A method of forming a real image floating in space, comprising: receiving light from an image source from a first direction along an optical axis; polarizing the light so as to create circularly polarized light having a first handedness; bouncing a first portion of the circularly polarized light between a broadband reflector-polarizer and a partially mirrored reflector along the optical axis so that the first portion of the circularly polarized light has a second handedness opposite the first handedness and is directed along the optical axis in a second direction opposite the first direction; after said bouncing of the first portion of the circularly polarized light, converting the first portion of the circularly polarized light to linearly polarized light along the optical axis; passing a second portion of the circularly polarized light through the broadband reflector-polarizer and the partially mirrored reflector along the optical axis so that the circularly polarized light retains the first handedness; after said passing of the second portion of the circularly polarized light, extinguishing the second portion of the circularly polarized light; and focusing the first portion of the circularly polarized light to a location in space so as to form a floating real image at the location.