Development of Dual Split-Ring Resonator for Electron Paramagnetic Resonance and Optically Detected Magnetic Resonance at 115 GHz*

Magnetic resonance (MR) uses microwaves to excite transitions between different spin states and to detect oscillating magnetic fields generated by coherently evolving spin superpositions. Most implementations of MR do this using resonant structures. The efficiency of both processes is enhanced when the Larmor Frequency of the spins coincides with the resonator mode such as the TE011 mode for the rectangular cavity. The local magnetic field at the center of this mode is enhanced roughly as  where Q ~ 10,000 at low field. However, at high magnetic field and high frequency, high quality factor resonators and thus high magnetic field enhancement has not been demonstrated as of yet. Here, we report on the development of the planar double split-ring resonator structure for applications at 115 GHz and high magnetic field.