Low loss 4H-SiC photonics for spin-quantum sensing

This work presents a comprehensive study on the development of planar integrated photonics for 4H silicon carbide (SiC) quantum sensors, with a focus on achieving high-performance and scalable devices. By leveraging high-volume SiC technology, we achieve a substantial reduction in optical losses, reaching 3.5 dB/cm at 785 nm, thereby surpassing the performance of previously reported planar SiC waveguides. A comprehensive analysis of the signal mode profile yields valuable insights into the modal characteristics of the waveguides, enabling the optimization of N-doping profiles for the optimal incorporation of V2 silicon vacancy color centers, which possess unique optical and spin properties essential for quantum sensing applications. Notably, our platform demonstrates broadband capability, supporting the development of both multi-mode and single-mode waveguides. Furthermore, we minimize surface roughness of the coupling facets to an root mean square value of 0.2 nm, thereby reducing scattering losses and enhancing device performance while maintaining compatibility with high-volume manufacturing processes. V2 color centers are created within the waveguide through proton implantation, as evidenced by the detection of fluorescence light above 850 nm within the guided waveguide mode, highlighting the potential of our platform for highly sensitive and compact SiC-based quantum sensors.