Light-reconfigured waveband-selective diffraction device enabled by micro-patterning of a photoresponsive self-organized helical superstructure†
A waveband-selective diffraction device, possessing dynamic and reversible light manipulation of its waveband-selectivity within a wide spectral range (∼140 nm), was developed by micro-patterning of a photoresponsive self-organized helical liquid crystal superstructure. Distinct from a conventional liquid crystal diffraction device, applied in a wide band from ultraviolet to near infrared wherein the diffracting light is due to the alternate phase modulation caused by the difference on liquid crystal arrangement, herein, the diffraction was mainly induced by an alternate transmittance/reflectance (i.e., amplitude) modulation to an incident light with a certain wavelength located in a selective reflection band of a binary patterned helical liquid crystal layer, producing diffraction both on the transmission and reflection sides of the sample. The waveband-selectivity was determined and manipulated by appropriately controlling the reflection band of the patterned helical liquid crystals. A prominent advantage compared to the majority of other liquid crystal polymer based devices is the electric responsiveness of such a device in addition to its photoresponsiveness. Moreover, an excellent light reconfiguration, exhibiting an erasing of the grating, followed by a rewriting of a Fresnel zone plate was achieved.