Optically Isotropic Polymer Stabilized Liquid Crystals with Fast and Large Field-Induced Refractive Index Variation

Optically isotropic polymer stabilized liquid crystals with low haze (~1% at 550 nm), large (~0.09) field induced refractive index variation, and fast (<0.1 ms) relaxation time are reported. The impressive improvement compared to previous studies using conventional nematic liquid crystals are due to both the addition of novel highly polar ferroelectric nematic liquid crystals that decrease the required field to achieve the theoretically predicted refractive index variation and of the 6 wt% of chiral dopant with high helical twisting power that suppressed the haze and made the system reversible with fast relaxation. It is also shown that the field induced refractive index variation can be increased over to 0.1 by using high intensity UV light for polymer stabilization. Although such polymer structure is not completely isotropic, it still provides polarization independent optical properties for normal incidence. Since fast and large switching of focal length is essential in AR/VR glasses, these systems offer significant potential for applications in highly tunable microlens arrays.