Ultrasound cholesteric liquid crystal color filter

We present an ultrasonically tunable color filter based on cholesteric liquid crystals (CLCs), where ultrasound excitation dynamically modulates the helical pitch. Three CLC cells with different chiral dopant concentrations (4 wt%, 7 wt%, and 12 wt%) were investigated. The 12 wt% dopant cell exhibited the most significant spectral shift, with the transmission peak shifting from 511 nm to 451 nm, under ultrasound actuation, achieving a 60-nm tunable range. Chromaticity analysis confirms a reversible color transition, demonstrating the effectiveness of ultrasound in dynamically tuning optical properties.