Full‐Spectrum Tunable and Handedness Invertible Geometric Phase Elements in Nanomotor‐based Spiral Superstructures

Abstract Photon‐based communications can remarkably expand information capacity due to their multidimensional physical properties, including amplitude, polarization, wavelength, and angular momentum. To manipulate light's properties, traditional static/bulky optical elements such as lenses, waveplates, holograms rely on the propagation effect to control phase of light. Ultrathin, multifunctional optical elements driven by miniaturization and system integration in the production of photonic devices are urgently needed. This study employs a micropatterned photoalignment technology to fabricate a series of beam‐shaping‐related planar chiro‐optical geometric phase elements (GPEs) based on nanomotor‐based cholesteric liquid crystals (CLCs). When the incident light's wavelength falls within the photonic bandgap (PBG) of the CLCs, the reflected beam acquires a spatially distributed phase modulation determined by the micropatterned CLC directors on the element substrate. This phenomenon, associated with Pancharatnam–Berry geometric phase, enables full 2π phase control of light. Through the unique photoisomerization‐induced chirality‐reversal property of nanomotors, continuous, reversible full‐spectrum PBG tuning and reversible switching of handedness can be achieved for each GPE. This work demonstrates both the design rule and experimental realization of advanced planar optical elements with advantages over traditional static/bulky devices. Importantly, it provides guidance for future efforts to achieve complete dimensional control of light in self‐organizing nanomotor‐based soft‐matter devices.