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The challenge of dynamic holographic video display based on spatial light modulator is that it requires a large spatial bandwidth product. A simple method is to reduce the size of a single pixel in conventional LCOS (liquid crystal on silicon , LCOS) device. However, with the pixel size shrinks, it also requires a corresponding reduction in thickness of liquid crystal cell, otherwise the fringe field effect between pixels will affect the modulation of normal pixel. A deep sub-wavelength metal grating with a Fabry-Perot resonance is used instead of the top electrode of LCOS to form a liquid crystal phase modulator in this paper. Different from traditional LCOS, which realizes the phase modulation by using the birefringence of the liquid crystal in liquid crystal cell, the birefringence of the liquid crystal in our device is used to modulate the conditions of the reflective boundary of the deep sub-wavelength metal grating, which in turn controls the amount of phase modulation of reflected light in grating slit. The TechWiz and CST Microwave Studios software are used in this paper. Observing the distribution of liquid crystal directors and electric field distribution. Recording the intensity of visible light reflection and observing whether the device can achieve phase modulation of 0 ~ 2π by changing the pixel pitch and grating structure parameters. The simulation results show that there is no significant change in the liquid crystal directors and electric field distribution in different pixel pitch, the device phase modulation is close to 2π , and it has a high reflectivity.
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