Wide-band tunable photonic bandgaps based on nematic-refilling cholesteric liquid crystal polymer template samples

This work first reports wide-band tunable photonic bandgap (PBG) devices based on nematic-refilling cholesteric liquid crystal polymer template samples. By changing the type of refilling nematic liquid crystal (NLC) and sample cell gap, the PBG features of the template sample can be crucially influenced. A physical model related with the NLC infiltration into the template nanopores based on capillary action is used to qualitatively explain the tunable PBG features of the refilling template samples. In addition, a nearly full white (480 nm − 720 nm) spatially tunable PBG device based on a NLC-refilling template wedge cell is demonstrated.