Vectorial optics with fine inhomogeneous polarization control are highly desired. Metasurfaces have been captivated a promising candidate, but their static post-fabrication geometry largely limits the dynamic tunability. Liquid crystal (LC) is usually employed as an additional index-changing layer together with metasurfaces. Unfortunately, most of the reported LCs only impart a varying but uniform phase on top of that from the metasurface, which we term “scalar” LC optics. Here, we pixelate a single-layer LC to display versatile and tunable vectorial holography, in which the polarization and amplitude could be arbitrarily and independently controlled at varying spatial positions. Furthermore, the subtle and vectorial LC-holography highlights the broadband and electrically-switchable functionalities. Our vectorial LC holography reveals significant opportunities for advanced cryptography, super-resolution imaging, and many other applications.

The increasing demand for the multidimensional and dynamic control of light has spurred the development of stimuli‐responsive, reconfigurable, and programmable optical systems. Liquid crystals (LCs), which combine liquid‐like stimuli‐responsiveness and crystal‐like orientational ordering, have emerged as highly appealing soft materials. Owing to their exceptional optical performance and programmable functionalities, they are becoming incredibly important materials in active planar optics and photonics. Additionally, silk proteins, luminescent materials, and metasurfaces exhibit dynamic optical properties, enabling remarkable multifunctional applications. This review focuses on the advancements in stimuli‐responsive materials, including LCs, silk proteins, luminescent materials, and active metasurfaces as well as some of these materials paired with LCs. Their attractive tunable applications in optics and photonics, along with the great potential for the future development of active optical systems, are also emphasized.

Simultaneous manipulation of multiple degrees of freedom of light lies at the heart of photonics. Nonlinear wavefront shaping offers an exceptional way to achieve this goal by converting incident light into beams of new frequencies with spatially varied phase, amplitude, and angular momenta. Nevertheless, the reconfigurable control over structured light fields for advanced multimode nonlinear photonics remains a grand challenge. Here, we propose the concept of nonlinear geometric phase in an emerging ferroelectric nematic fluid, of which the second-order nonlinear susceptibility carries spin-dependent nonlinearity phase. A case study with photopatterned q-plates demonstrates the generation of second-harmonic optical vortices with spin-locked topological charges by using cascaded linear and nonlinear optical spin-orbit interactions. Furthermore, we present the dynamic tunability of second-harmonic structured light through temperature, electric field, and twisted elastic force. The proposed strategy opens new avenues for reconfigurable nonlinear photonics, with potential applications in optical communications, quantum computing, high-resolution imaging, etc.

Planar optical elements incorporating space-varying Pancharatnam-Berry phase have revolutionized the manipulation of light fields by enabling continuous control over amplitude, phase, and polarization. While previous research focusing on linear functionalities using apolar liquid crystals (LCs) has attracted much attention, extending this concept to the nonlinear regime offers unprecedented opportunities for advanced optical processing. Here, we demonstrate the reconfigurable nonlinear Pancharatnam-Berry LC diffractive optics in photopatterned ion-doped ferroelectric nematics. By customizing the spatial phase distribution of efficient second-harmonic excitation, we accomplish programmable beam steering of various optical states towards predefined diffraction directions. Experimental results reveal continuous evolution of diffraction orders, intensity distributions, and polarization states under electrically varying splay conditions, consistent with our theoretical predictions. This work opens new avenues for designing reconfigurable nonlinear beam shaping and steering devices with potential applications in advanced optical and quantum information processing.

Complex polar topological configurations are the foundation for exploring exotic phases and nontrivial emergent phenomena in condensed-matter physics. While numerous topological configurations like skyrmions and merons are known to occur spontaneously in various materials, achieving the designability of magnetically- and electrically-polar textures in a controlled manner is a long-standing challenge in domain engineering. Here, we discover an unprecedented mesophase that exhibits unipolar and bipolar orders, where both apolar and polar orientational order parameters are modulated. The polar state enables defect-free polar patterning with designability and controllability on large scales. A case study demonstrates the facile generation of second-harmonic perfect vector beams through photopatterned topological polar liquid crystal superstructures. Remarkably, this single-layer, micrometer-thin-film device attains functionalities comparable to multiple conventional optical components, establishing a foundation for advanced nonlinear vectorial optics at the micrometer scale.

Actuators mimic the unique motion of bacteria, which are realized by self-organizing photoresponsive cholesteric liquid crystals.