Holographic optical apparatus, holographic optical system, and holographic display system

A holographic optical apparatus, comprising:

• a beam splitting component configured to split received light into reference light and signal light, and output the reference light and the signal light, the reference light and the signal light being coherent light;
• a focal length modulation component including a plurality of focal length modulation regions, focal lengths of the plurality of focal length modulation regions being different from each other;
• an optical element including a recording medium layer, the recording medium layer including a plurality of recording regions, and each recording region being located in a light-exit path of a focal length modulation region;
• and
• a transmission assembly disposed in a light-exit path of the beam splitting component, the transmission assembly being configured to transmit the reference light to the plurality of recording regions, and transmit the signal light to the plurality of focal length modulation regions,
• wherein the recording medium layer is configured to receive the signal light after being modulated by the focal length modulation region, and record interference fringes generated by interference between the signal light and the reference light in the recording region
• wherein the transmission assembly includes:
• a first transmission portion configured to transmit the reference light to the plurality of recording regions;
• a second transmission portion configured to transmit the signal light to part of the plurality of focal length modulation regions;
• and
• a third transmission portion configured to transmit the signal light to a remaining part of the plurality of focal length modulation regions.