The light cage - An on-chip hollow-core waveguide implemented by 3D nanoprinting

Strong light-matter interaction is essential for various applications in biochemical sensing, quantum information processing and magnetometry. Along with recent developments of integrated photonic devices on silicon chips, integrated on-chip waveguides have become an attractive platform for light-matter interaction. The solid-core nature of the many planar waveguides limits the degree of overlap between electromagnetic field and matter. To tackle this boundary, different solutions have been proposed, such as slot waveguides [1] and anti-resonant reflecting optical waveguides (ARROWs) [2]. They exploit either evanescent fields outside the core or strong mode concentration in the slot. However, slot modes are usually on the nanometer range thus limiting the light-matter interaction volume. On the other hand, analyte access to the core of ARROWs is through their open ends, leading to long diffusion times.