Transmittance optimization of a liquid crystal cladding waveguide beam steerer based on the liquid crystal fringe field effect

Steerable electro-evanescent optical refractor (SEEOR), empowered by liquid crystal waveguide technology, presents advantages including compact size, continuous beam scanning, and high speed. These attributes demonstrate its considerable potential for applications in fields such as light detection and ranging (LiDAR) and projection display. However, a significant limitation of this technology is the light utilization efficiency. This paper reveals the loss of waveguide mode mismatch at the refractive interface in the liquid crystal waveguide beam scanner. A simulation model of the beam deflection process has been developed based on Maxwell's equations. It indicates that the fringe field effect of liquid crystal significantly influences the interface loss. By exploiting the continuous refractive index distribution characteristics in the liquid crystal fringe field region, adiabatic coupling transmission was achieved at the interface, thereby effectively improving both the light energy utilization efficiency and stability of the device. With the application of fringe field effect optimization, the average transmissivity of each refractive interface can be significantly enhanced, up to 99.8% (experimental test result over 99.7%). These advancements provide important guidance for the progress of high-energy efficiency liquid crystal waveguide devices and facilitate the implementation of SEEOR in applications such as LiDAR and autonomous driving.