Strong Coupling of Magnons to Microwave Photons in Three-Dimensional Printed Resonators

We report on ferromagnetic resonant mode hybridization in reentrant cavities made with a commercial three-dimensional (3-D) printer, followed by conventional 3-D metallization with copper and tin. The cavity volume was only 7% that of a standard cavity resonating at the same frequency while maintaining a high quality factor. Simulations were in very good agreement. We obtained an effective coupling of about 40 MHz in two cavities at room temperature. These experimental results demonstrate the utility of tunable filters based on complex 3-D printed cavities.