Conjugate wavefront encoding: an efficient eyebox extension approach for holographic Maxwellian near-eye display

Conventional holographic display suffers from the conjugate light issue. In this Letter, we propose to efficiently extend the eyebox of holographic Maxwellian near-eye display by encoding the conjugate wavefront as the multiplication of plane wave phase with the target image. It is interesting that after being focused by the lens, the generated conjugate viewpoints also present erect virtual images with the same image quality as the signal viewpoints. Multiple plane wave encoding is used for eyebox extension, and, because of the utilization of conjugate light, the effect of eyebox extension is doubled. That is, the space bandwidth of the amplitude-type hologram is fully used. A speckless holographic image is produced in mid-air with high quality within a large depth range. The proposed display is compact and promising for the augmented reality near-eye display. Furthermore, it may inspire better solutions for the conjugate light issue of amplitude-type holography.