Liquid‐Crystal‐Mediated Active Waveguides toward Programmable Integrated Optics

Abstract Optics, playing an ever‐important role in life, is developing toward miniaturization and integration. Particularly, the field programming of integrated optics will benefit its functionality and durability, thus is highly pursued. Here, through precisely controlling the space‐variant orientations of anisotropic liquid crystals (LCs), various graded‐index waveguides are demonstrated in a homogeneous medium. Straight/bending waveguides and ring resonators are fabricated via LC photopatterning. They exhibit pronounced polychromatic light‐guiding performance. Thanks to their intrinsic external‐stimuli responsivity, the thermal switchability and polarization tunability are verified. By selectively polymerizing, robust functional components and active connecting waveguides can be realized on the same chip. It provides a practical and universal solution to programmable integrated optics, and extends the applications of microstructured soft matter even in wearable photonics.