Photocontrol of selective light reflection by oblique helicoidal cholesteric

An oblique helicoidal cholesteric ChOH represents a unique optical material with a pitch that can be tuned by an electric or magnetic field in a broad range from sub micrometers to micrometers. In this work, we demonstrate that the oblique helicoidal cholesteric doped with azoxybenzene molecules and stabilized by an electric field could also be tuned by light irradiation. At a fixed voltage, UV irradiation causes a redshift of the reflection peak by more than 200 nm. The demonstrated effect has the potential for applications such as smart windows, sensors, tunable lasers, and filters.