Electrically tunable properties of wideband-absorptive and reflection-selective films based on multi-dichroic dye-doped cholesteric liquid crystals

This work demonstrated an electrical switch of thin film with Bragg reflection and wideband light absorption characteristics based on three commercially available azobenzene-dichroic dye-doped cholesteric liquid crystals (LCs). The effect of the pitch of cholesteric LCs on their electro-optical characteristics and laser protection properties (=532nm) was investigated in detail. Experimental results showed that such electrically tunable films had advantages of a fast response time, a polariser-free, low power consumption and high transmittance. Moreover, the transmittance of the thin films can be easily modulated by applying an electric field. It therefore exhibited the potential application as laser protective systems against the damage to the sensor or human's eye from a laser.