Fast electro-optical switching of dichroic dye-doped antiferroelectric liquid crystals without polarizers

In this work we investigate alignment and electro-optical properties of a room temperature dye-doped antiferroelectric liquid crystal mixture. We achieved extremely uniform alignment on macroscopic scale of thin cells with the combination of proper surface alignment and electric field treatment. We have also successfully demonstrated that two films of dye-doped antiferroelectric liquid crystals in their anticlinic chiral smectic C (SmC_A*) phase can be used to switch the transmitted light intensity between dark and bright states without the need of polarizer filters. We also demonstrate that one could get either normally dark or bright states. Normally dark states can be useful in number of applications such as in privacy windows or smart refrigerators. A normally transparent display has applications in plethora of other areas, such as navigation systems built in windshields, in goggles, or smart windows.