Highly tunable 3D liquid photonic crystals are demonstrated using low-dc-field-driven polymer-stabilized blue-phase liquid crystals. The central wavelength of the photonic band gap can be reversibly shifted to more than 200 nm away from the original position. Besides, by controlling the polymerization-induced morphology variations, the band gap can also be expanded from a bandwidth of around 30 nm to at least 310 nm, the first time a “white” blue phase is observed. Both types of band-gap modulation, namely, shifting and expansion, can be independently manipulated in any crystal axis without affecting the lattice spacings in the other dimensions. We envision polymer-stabilized blue-phase liquid crystals as a fascinating platform for photonic applications, such as 3D lasers, nonlinear optics, and photonic integrated circuits.

Self-organized 3D liquid crystalline photonic nanostructures with high light-directed controllability are developed by doping azobenzene-functionalized bent-shaped molecules.

Glass with multiple light control functions has received considerable attention in recent years. This study demonstrates a multifunctional smart glass composed of hybrid‐aligned ion‐doped nematic liquid crystals (LCs). In the absence of an applied electric field, the hybrid aligned LC is transparent and can be used for light field shaping. The transmittance of the glass can be limited to less than 2% with a 1D oblique viewing angle of >50°. In addition, by varying the frequency and strength of the electric field applied to the device, tinted and scattering states can be achieved with polarization rotation and the electrohydrodynamic effect, respectively. The nonscattering tinted state can control transmittance in the range from 38% to 0.2%. The scattering state provides a 99% high‐haze performance. These results demonstrate that the proposed smart glass can be used for meeting the novel requirements of the next generation of green and smart buildings and vehicles.

Manipulating the polarization orientation of light is essential in modern optics, biology, and related fields, but the strong optical dispersion inherent in current polarization rotators severely restricts their use to single-frequency lasers and their flexibility in system design. Many attempts have been made to realize dispersionless polarization rotation, usually by designing a complex set of wave plates with mutually compensated dispersions. Here, enabled by a thin cell of hybrid splay–twist liquid crystal, we demonstrate a tunable achromatic polarization rotator that is free of dispersion engineering. The optic axis distribution in the liquid crystal cell can be dynamically controlled by an applied electric field and allows an input polarization vector to be continuously rotated up to 90° (or 180° in a tandem-cell geometry) in an adiabatic and nondispersive manner. The proposed mechanism can be further implemented to construct spatial light modulators for single-path ultrabroadband generation of complex vector fields from uniformly polarized light.

Linear polarization rotators have been widely used in optical systems. Commonly used polarization rotators are still beset by strong dispersion and thus restricted spectral bandwidth of operation. This leads to the development of achromatic or broadband alternatives, but most of them incorporate multiple waveplates for retardation compensation, which comes at the cost of increased complexity and reduced flexibility in operation and system design. Here, we demonstrate a single-element achromatic polarization rotator based on a thin film of dual-frequency chiral liquid crystal. The angle of polarization rotation is electrically tunable from 0° to 180° with low dispersion (±3°) in the entire visible spectrum, and a high degree of linear polarization (>95%) at the output.