Advances in Versatile Light Field Manipulation with On-Chip Metasurfaces

The relentless pursuit of higher information density and processing speed has driven photonic chips toward miniaturization, high performance, and multifunctional integration. Metasurfaces, composed of subwavelength artificial meta-atoms, have emerged as a revolutionary platform for manipulating light fields at the nanoscale, offering unprecedented control over amplitude, phase and polarization, as well as enabling frequency conversion through nonlinear processes. When seamlessly integrated with on-chip optical waveguides, metasurfaces provide a compelling solution for bridging guided waves and free-space waves, enabling compact, high-performance photonic devices with versatile light-manipulation capabilities. This review systematically surveys recent advances in on-chip metasurfaces for multifunctional light field manipulation, with a focus on guided-wave radiation control. We first elucidate the fundamental phase modulation mechanisms that collectively constitute a versatile toolbox for tailoring light fields at subwavelength scales. We then examine the three core application scenarios that define the operational framework of metasurface-integrated photonic systems: free-space-to-chip coupling, in-plane guided-wave manipulation, and guided-wave-to-free-space radiation. For each scenario, we highlight representative device architectures and their performance characteristics, tracing the evolution from single-mechanism modulation to multidimensional multiplexing and dynamic reconfigurability. We conclude by discussing remaining challenges including efficiency, dynamic tunability, and scalable fabrication, and outline future directions such as intelligent inverse design, on-chip quantum metasurfaces, and optical computing.