Confocal photoluminescence mapping of diamond photonic crystal cavity modes for the silicon vacancy center

Diamond photonic crystal cavities offer exceptional properties for interfacing color centers in diamond to integrated photonic circuits. Leveraging Purcell enhancement of the color centers' emission into the zero-phonon line, the development of high quality, low mode volume single-crystal diamond resonators remains one of the key challenges for building diamond quantum networks. In this paper, we present both a robust, versatile photonic crystal design as well as a scalable fabrication process realizing suspended nanobeam cavities. Measurements of confocal microscopy with broadband excitation yield quality factors of more than 5000. We further demonstrate a fast and facile characterization of our structures based on confocal photoluminescence imaging. This method not only provides a more detailed look at the higher order modes within diamond nanobeam resonators but also serves as a non-destructive diagnostic of the modes' susceptibility to fabrication imperfections, providing critical feedback for scalable, high-yield integrated quantum photonic device development.