Voltage-Controlled Magneto-Optical Spatial Light Modulators with Grayscale Capability Level

Magneto-optical spatial light modulators (MOSLMs), utilizing the magneto-optical (MO) effect, are well suited for the narrow-pitch pixels required to realize holographic images with a wide viewing zone. To achieve both a high pixel density and low power consumption, we have proposed a voltage-controlled MOSLM (VC-MOSLM) that applies dynamic magnetization reversal based on voltage-controlled magnetic anisotropy (VCMA), which consumes considerably less power in comparison to current-driven MOSLMs. This study investigated the potential for displaying gray levels using an MO pixel comprising multiple sub-structures with different shapes that are driven by VCMA. The micromagnetic simulation results indicate that the pixel can be partially or fully switched by adjusting the pulse width of the applied voltage; this is because the precession period of a sub-structure depends on its shape. This means that although our VC-MOSLM exhibits binary expression, we can realize gray levels in a pixel trough partial switching. This grayscale potential is highly beneficial for improving the quality of reconstructed holographic images.