Photonic band gap materials have the ability to modulate light. When they can be dynamically controlled beyond static modulation, their versatility improves and they become very useful in scientific and industrial applications. The quality of photonic band gap materials depends on the tunable wavelength range, dynamic controllability, and wavelength selectivity in response to external cues. In this paper, we demonstrate an electrically tunable photonic band gap material that covers a wide range (241 nm) in the visible spectrum and is based on a monodomain blue-phase liquid crystal stabilized by nonmesogenic and chiral mesogenic monomers. With this approach, we can accurately tune a reflection wavelength that possesses a narrow bandwidth (27 nm) even under a high electric field. The switching is fully reversible owing to a relatively small hysteresis with a fast response time, and it also shows a wider viewing angle than that of cholesteric liquid crystals. We believe that the proposed material has the potential to tune color filters and bandpass filters.

We propose an electrically tunable narrow bandwidth bandpass filter in which the band gap of polymer stabilized blue phase liquid crystal (PS-BPLC) with distinct crystallographic orientations can be tuned on electric field sweeps from red to blue with a narrow bandwidth (27 nm). Owing to the narrow bandwidth which can cut specific wavelength, it could be used as a filter to enhance color gamut in LCDs. In addition, the proposed bandpass filter exhibits much wider viewing angle property than Cholesteric LC bandpass filter.