Optimized optical catenary structures empower compact on-chip polarization detector

Abstract

Polarized light has various applications in industrial inspection, remote sensing, and other fields. Traditional methods for detecting polarized light typically rely on the polarization properties of optical components or specific materials to detect and analyze light with different polarization states. However, the polarization detection system designed by these methods has a complex optical path, resulting in bulky size and high cost in large-scale integrated applications, thus hindering the development and application of polarization detection. Therefore, it is crucial to develop polarization detectors to meet the requirements of compact and highly integrated optical devices. The optical catenary structure is a kind of continuous metasurface structure, which has continuous, linear phase change and abundant electromagnetic modes. To further miniaturize the polarization detector for on-chip applications, a potential approach is to combine silicon waveguide with metasurface to achieve a compact, high-efficiency polarization detector. In this work, the on-chip beam polarization detector is effectively realized by using one single catenary gold nanostructure loaded atop silicon on an insulator (SOI) waveguide, which is optimized by the Particle Swarm Optimization algorithm. We envision that our finding could facilitate the application of polarization-optical devices and systems in various fields, including sensing, optical communications, imaging, quantum sciences, etc.