A mode-switchable backlight comprising a first directional backlight comprising an array of narrow-angle emitters configured to provide narrow-angle emitted light during both a first mode and a second mode, wherein a narrow-angle emitter of the narrow-angle emitter array comprises an active optical emitter configured to provide the narrow-angle emitted light; and a second directional backlight comprising an array of bidirectional emitters configured to provide bidirectional emitted light exclusively during the second mode, the bidirectional emitted light having a bifurcated angular extent that is complementary to an angular range of the narrow-angle emitted light, wherein a bidirectional emitter of the bidirectional emitter array comprises a pair of active optical emitters, a first active optical emitter of the active optical emitter pair being configured to provide a first segment of the bidirectional emitted light and a second active optical emitter of the active optical emitter pair being configured to provide a second segment of the bidirectional emitted light, wherein a combination of the narrow-angle emitted light and the bidirectional emitted light during the second mode is configured to provide broad-angle emitted light having an angular range that is a summation of the angular range of the narrow-angle emitted light and the bifurcated angular extent of the bidirectional emitted light and characterized in that the first directional backlight is configured to provide the narrow-angle emitted light from a first surface, wherein the second directional backlight is adjacent to a second surface of the first directional backlight opposite to the first surface, and wherein the first directional backlight is transparent to the bidirectional emitted light. a first directional backlight comprising an array of narrow-angle emitters configured to provide narrow-angle emitted light during both a first mode and a second mode, wherein a narrow-angle emitter of the narrow-angle emitter array comprises an active optical emitter configured to provide the narrow-angle emitted light; and a second directional backlight comprising an array of bidirectional emitters configured to provide bidirectional emitted light exclusively during the second mode, the bidirectional emitted light having a bifurcated angular extent that is complementary to an angular range of the narrow-angle emitted light, wherein a bidirectional emitter of the bidirectional emitter array comprises a pair of active optical emitters, a first active optical emitter of the active optical emitter pair being configured to provide a first segment of the bidirectional emitted light and a second active optical emitter of the active optical emitter pair being configured to provide a second segment of the bidirectional emitted light, wherein a combination of the narrow-angle emitted light and the bidirectional emitted light during the second mode is configured to provide broad-angle emitted light having an angular range that is a summation of the angular range of the narrow-angle emitted light and the bifurcated angular extent of the bidirectional emitted light and characterized in that the first directional backlight is configured to provide the narrow-angle emitted light from a first surface, wherein the second directional backlight is adjacent to a second surface of the first directional backlight opposite to the first surface, and wherein the first directional backlight is transparent to the bidirectional emitted light. <EOS>