Quantized phase-only hologram generation based on an iterative algorithm with time-multiplexing.

Holographic display, as one of the most promising three-dimensional visualization technologies, faces dynamic advancement constraints due to the inherent trade-off between spatial light modulators refresh rates and holographic data volume. However, low-bit-depth solutions enable significantly higher refresh rates, thereby fulfilling the critical demand for dynamic display. This study proposes a quantized stochastic gradient descent iterative algorithm that enables direct-generation of 4-bit-depth phase-only holograms at 2K resolution. By implementing a differentiable quantization constraint, we successfully compress conventional 8-bit holograms to 4-bit depth while accelerating convergence through the same quantization strategy embedded in the initial random phase map. The time-multiplexing technique is employed to suppress quantization-induced speckle during reconstruction. Both numerical simulations and optical experiments demonstrate that quantized holograms perform better than traditional iterative algorithms in terms of reconstruction quality. This method provides an efficient solution for data-intensive applications including dynamic holographic displays and low-power holographic storage systems.