Provided is a liquid crystal grating including: a first substrate; a second substrate opposite to the first substrate; a liquid crystal layer between the first substrate and the second substrate; a first electrode structure on the first substrate; and a second electrode structure on the second substrate. The first electrode structure and the second electrode structure are configured to receive control signals, the control signal including a first set of control signals and a second set of control signals; to cause the liquid crystal grating to have a first grating pitch in response to the first set of control signals; and to cause the liquid crystal grating to have a second grating pitch in response to the second set of control signals, the second grating pitch being different from the first grating pitch.