Disclosed are a holographic display method and a holographic display device. The holographic display method includes: acquiring an area of Nth diffraction order corresponding to an eye position; according to the area of Nth diffraction order, calculating a holographic complex amplitude distribution corresponding to a window of Nth diffraction order to obtain window hologram information, a function of the holographic complex amplitude distribution being expressed by C(m,n)=A(m,n)*exp[−iφ(m,n)/N]; encoding the window hologram information; and according to the encoded window hologram information, loading the encoded window hologram information in the area of Nth diffraction order to display a hologram.

Methods, apparatus, devices, and systems for displaying three-dimensional objects by individually diffracting different colors of light are provided. In one aspect, an optically diffractive device includes: first and second diffractive components and a color-selective polarizer therebetween. The first diffractive component is configured to diffract a first color of light in a first polarization state incident at a first incident angle with a first diffraction efficiency at a first diffracted angle, and diffract a second color of light in a second polarization state with a diffraction efficiency substantially less than the first diffraction efficiency. The color-selective polarizer is configured to rotate the second polarization state of the second color of light to the first polarization state. The second diffractive component is configured to diffract the second color of light in the first polarization state with a second diffraction efficiency at a second diffracted angle substantially identical to the first diffracted angle.

Methods, apparatus, devices, and systems for displaying three-dimensional objects by individually diffracting different colors of light are provided. In one aspect, a system includes a display having a plurality of display elements and an optical device including 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 including a plurality of different colors of light.

The holographic Christmas tree is a holographic device. The holographic Christmas tree projects a three-dimensional image of a Christmas tree. The holographic Christmas tree includes a pedestal, a holographic projector, a substrate, and an image. The image is the three-dimensional image of a Christmas tree. The holographic substrate projects the image into the substrate. The pedestal contains the holographic projector.

Methods, apparatus, devices, and systems for reconstructing three-dimensional objects with display zero order light suppression are provided. In one aspect, a method includes illuminating a display with light, a portion of the light illuminating display elements of the display, and modulating the display elements of the display with a hologram corresponding to holographic data to diffract the portion of the light to form a holographic scene corresponding to the holographic data, and to suppress display zero order light in the holographic scene. The display zero order light can include reflected light from the display.

Methods, apparatus, devices, and systems for reconstructing three-dimensional objects with display zero order light suppression are provided. In one aspect, a method includes illuminating a display with light at an incident angle, a portion of the light illuminating display elements of the display, modulating the display elements of the display with a hologram corresponding to holographic data to diffract the portion of the light to form a holographic scene corresponding to the holographic data, and redirecting display zero order light away from the holographic scene to suppress the display zero order light in the holographic scene. The display zero order light includes reflected light from the display.

Methods, apparatus, devices, and systems for reconstructing three-dimensional objects with display zero order light suppression are provided. In one aspect, a method includes illuminating a display with light at an incident angle, a portion of the light illuminating display elements of the display, modulating the display elements of the display with a hologram corresponding to holographic data to diffract the portion of the light to form a holographic scene corresponding to the holographic data, and redirecting display zero order light away from the holographic scene to suppress the display zero order light in the holographic scene. The display zero order light includes reflected light from the display. The light includes a plurality of different colors of light.

Methods, apparatus, devices, and systems for displaying three-dimensional objects by individually diffracting different colors of light are provided. In one aspect, an optically diffractive device includes: first and second diffractive components and a color-selective polarizer therebetween. The first diffractive component is configured to diffract a first color of light in a first polarization state incident at a first incident angle with a first diffraction efficiency at a first diffracted angle, and diffract a second color of light in a second polarization state with a diffraction efficiency substantially less than the first diffraction efficiency. The color-selective polarizer is configured to rotate the second polarization state of the second color of light to the first polarization state. The second diffractive component is configured to diffract the second color of light in the first polarization state with a second diffraction efficiency at a second diffracted angle substantially identical to the first diffracted angle.

Methods, apparatus, devices, and systems for reconstructing three-dimensional objects with display zero order light suppression are provided. In one aspect, a method includes illuminating a display with light, a portion of the light illuminating display elements of the display, and modulating the display elements of the display with a hologram corresponding to holographic data to diffract the portion of the light to form a holographic scene corresponding to the holographic data, and to suppress display zero order light in the holographic scene. The display zero order light can include reflected light from the display.

Methods, apparatus, devices, and systems for displaying three-dimensional objects by individually diffracting different colors of light are provided. In one aspect, a system includes a display having a plurality of display elements and an optical device including 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 including a plurality of different colors of light.