Wide-angle lasing from photonic crystal nanostructures of a liquid-crystalline blue phase
Wide-angle lasing emitting from dye-doped blue-phase liquid crystals (DDBPLCs), which are analogous to photonic crystals, have been demonstrated to selectively reflect visible light. Herein, the best mixed system ZTO-5024LA+S811 was chosen as it required minimal applied voltage for wavelength tuning and exhibited largest platelets of several hundred micrometers with homogeneous colors in the BP lattice; the BP sample integrated with in-plane switching (IPS) electrodes, which enhanced the electric field directionally, demonstrated wideband tunability of Bragg light reflection up to around 70 nm when measured at various detection angles. The results show that to obtain the same amount of reflection peak shift for the 0° detection angle, lowest voltage was required because the largest electrostriction effect stretched the photonic band gap (PBG) structure under the transverse electric field constituted by the IPS electrodes. By the addition of a laser dye, PYRROMETH-597, to the BP sample, the lasing action was achieved with wavelength tunable over 55 nm for each detection angle. This miniaturized and simple design presents significant possibilities for easy packaging into displays and the fabrication of spatially wavelength-tunable photonic devices.