Displaying three-dimensional objects

A system comprising:

• a display comprising a plurality of display elements;
• and
• an optical device comprising at least two beam expanders configured to expand an input light beam in at least two dimensions to generate an output light beam to the display by diffracting the input light beam to adjust a beam size of the input light beam in the at least two dimensions, the input light beam comprising a plurality of different colors of light,
• wherein a front surface of the display and a back surface of the optical device are attached together by an intermediate layer, and
• wherein the intermediate layer is configured to have a refractive index lower than a refractive index of a layer of the optical device, such that each of the plurality of different colors of light transmitted at zero order by the optical device is totally reflected at an interface between the intermediate layer and the layer of the optical device.

A system comprising:

• an illuminator configured to provide an input light beam comprising a plurality of different colors of light, wherein the illuminator comprises a plurality of light emitting elements each configured to emit a respective color of light;
• and
• an optical device arranged adjacent to the illuminator, the optical device comprising at least two beam expanders configured to expand the input light beam in at least two dimensions to generate an output light beam to a display comprising a plurality of display elements by diffracting the input light beam to adjust a beam size of the input light beam in the at least two dimensions, wherein the optical device is configured to diffract the plurality of different colors of light in the input light beam, such that, when the plurality of different colors of light is incident on the optical device, the optical device separates light of individual colors of light while suppressing crosstalk between the plurality of different colors of light;
• a controller coupled to the illuminator and configured to control the illuminator to provide each of the plurality of different colors of light,
• wherein the controller is coupled to the display and configured to transmit a respective control signal to each of the plurality of display elements for modulation of at least one property of the display element,
• wherein the controller is configured to:
• obtain graphic data comprising respective primitive data for a plurality of primitives corresponding to an object in a three-dimensional space;
• determine, for each of the plurality of primitives, an electromagnetic (EM) field contribution to each of the plurality of display elements of the display;
• generate, for each of the plurality of display elements, a sum of the EM field contributions from the plurality of primitives to the display element and generate, for each of the plurality of display elements, the respective control signal based on the sum of the EM field contributions to the display element, and
• wherein the controller is configured to:
• sequentially modulate the display with information associated with the plurality of different colors of light in a series of time periods, and control the illuminator to sequentially emit each of the plurality of different colors of light to the optical device during a respective time period of the series of time periods, such that each of the plurality of different colors of light is diffracted by the optical device to the display and reflected by modulated display elements of the display to form a respective color three-dimensional light field corresponding to the object during the respective time period, and
• wherein the controller is configured to modulate the display such that the respective color three-dimensional light field appears fully in front of the display, fully behind the display, or partially in front of the display and partially behind the display.