Uniform and patterned orientation of a crystallographic direction of ordered materials is of fundamental significance and of great interest for electronic and photonic applications. However, such orientation control is generally complicated and challenging with regard to inorganic and organic crystalline materials due to the occurrence of uncontrollable dislocations or defects. Achieving uniform lattice orientation in frustrated liquid-crystalline phases, like cubic blue phases, is a formidable task. Taming and tailoring the ordering of such soft, cubic lattices along predetermined or desired directions, and even imparting a prescribed pattern on lattice orientation, are more challenging, due to the entropy-domination attribute of soft matter. Herein, we disclose a facile way to realize designed micropatterning of a crystallographic direction of a soft, cubic liquid-crystal superstructure, exhibiting an alternate uniform and random orientation of the lattice crystallographic direction enabled by a photoalignment technique. Because of the rewritable trait of the photoalignment film, the pattern can be erased and rewritten on-demand by light. Such an oriented soft lattice sensitively responds to various external stimuli such as temperature, electric field, and light irradiation. Furthermore, advanced reflective photonic applications are achieved based on the patterned crystallographic orientation of the cubic blue phase, soft lattice.
Multidimensional and large‐scale parallel manipulation of light, especially on‐demand tailoring of the working frequency and spatial phase front, is highly pursued in modern optics. Here, broadband tunable planar optics is demonstrated by electrically driving the nanohelix of photopatterned heliconical cholesterics. By preprogramming the initial orientation of the helixes using a dynamic‐mask photoalignment technique, spatial geometric phases can be arbitrarily encoded to the reflected light in a reconfigurable way. Due to the reversible electrically variant pitch of the heliconical superstructures, the reflective Bragg band can be precisely selected in the range from 380 to 1550 nm. In addition to wavelength selection and geometric phase modulation, spatial amplitude modulation and spin reversion can be further expected. This may offer a platform for full‐dimensional manipulation of light, including wavelength/frequency, phase, amplitude, time, and spin, thus upgrading optical information processing techniques.
Achieving a coexistence of two or multiple phases of soft matters via a delicate trade‐off of free energy and long‐range order with one another has been inspiring abundant interest on fundamental sciences and engineering. In this work, a stable coexistence of the optically achiral‐anisotropic liquid crystalline nematic phase and the optically chiral‐isotropic liquid crystalline blue phase is proposed and demonstrated, with their distribution tailored in a micro‐pattern by the developed localized micro‐regional polymer templating technique. Such a stable patterned coexistence of the two different phases with a distinct molecular arrangement, optical chirality, and anisotropy is achieved depending on a delicate matching of the elastic energy on the interface between liquid crystals and polymer networks. In contrast to the majority of soft coexistence systems, a specific dynamic and reversible on–off response of chirality and anisotropy is observed in such a system driven by an electric field. The structure of patterned coexistence system in the presence and absence of external stimulation is explored by microscopy and optical technique, and furthermore, the prospective photonic applications are demonstrated. This investigation indicates another category of functional soft material with fantastic adaptive characteristics for application in optics, electronics, interface physics, and chemistry.
Structural colours have broad applications in advanced photonics due to the versatile advantages of fade-resistant, high resolution and saturation. Nevertheless, leveraging the structural colours of adaptive systems with dynamical wide-colours...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.