Holographic display apparatus and hologram optimization method therefor

A holographic display apparatus comprising:

• a focus-forming optical element configured to form a plurality of foci by receiving plane waves;
• a collimating lens configured to propagate, as plane waves, light incident through the plurality of foci;
• a spatial light modulator configured to generate a holographic image by overlapping a plurality of plane waves incident from the collimating lens;
• and
• an optimizer configured to generate a predictive hologram obtained by back-propagating the holographic image, generate a predictive holographic image for the predictive hologram through a model simulating an optical system of a holographic display, and repeat a process of generating the predictive hologram and the predictive holographic image until a value of a loss function between the predictive holographic image and a predefined target image is less than a predefined threshold, by using a gradient descent method.

An optimization method of a holographic display, the optimization method comprising:

• forming a plurality of foci with respect to plane waves by using a focus-forming optical element;
• propagating, as plane waves, light incident through a collimating lens through the plurality of foci;
• by a spatial light modulator, generating a holographic image by overlapping a plurality of plane waves incident from the collimating lens;
• and
• measuring aberration by using an image captured by making the holographic image and a reference wave interfere with each other, and reflecting a complex wavefront corresponding to inverse of the measured aberration, in the spatial light modulator.

An optimization method of a holographic display, the optimization method comprising:

• forming a plurality of foci with respect to plane waves by using a focus-forming optical element;
• propagating, as plane waves, light incident through a collimating lens through the plurality of foci;
• by a spatial light modulator, generating a holographic image by overlapping a plurality of plane waves incident from the collimating lens;
• and
• generating a predictive hologram obtained by back-propagating the holographic image;
• generating a predictive holographic image about the predictive hologram through a model simulating an optical system of the holographic display;
• calculating a loss function between the predictive holographic image and a predefined target image;
• and
• repeating from the generating of the predictive hologram to the calculating of the loss function until a value of the loss function is less than a predefined threshold, by using a gradient descent method.