Fringe field effect free high-resolution display and photonic devices using deformed helix ferroelectric liquid crystal

The fringe field effect (FFE) is one of the biggest bottlenecks for the display, and the photonic industry limiting the pixel per inch (PPI) to ~450. The modern applications such as AR/VR headsets and photonic elements such as wavelength selective switches required significantly higher PPI panel. Despite the rigorous research efforts, conventional LCs still show serious FFE, and therefore, hinder the progress of high PPI display and photonic elements. In this article, we studied FFE in the deformed helix ferroelectric liquid crystals (DHFLCs) and found that the subwavelength pitch of the DHFLCs is critically important to suppress the FFE. These DHFLCs show no FFE, for the electric field parallel to the FLC helix, however, we have observed some FFE for the electric field perpendicular to the FLC helix. Additionally, we have found that the high-frequency driving further suppresses the FFE. Later, we deployed DHFLCs to diffraction grating and display to confirm our findings. The proposed DHFLCs with subwavelength pitch can support pixel density up to 4233 PPI for displays, and up to 12,700 PPI for monochromatic photonic devices. Thus, the fast switchable DHFLCs with subwavelength pitch pave the way for the high-pixel density display and photonic devices.