A system for magnetic detection includes a magneto-optical defect center material comprising a plurality of magneto-optical defect centers, an optical light source, an optical detector, and a radio frequency (RF) excitation source. The optical light source is configured to provide optical excitation to the magneto-optical defect center material. The optical detector is configured to receive an optical signal emitted by the magneto-optical defect center material. The RF excitation source is configured to provide RF excitation to the magneto-optical defect center material. The RF excitation source includes an RF feed connector, and a metallic material coated on the magneto-optical defect center material and electrically connected to the RF feed connecter.