Phase control of multi-RF photon spectroscopy of spin centers in SiC

The spin manipulation of silicon vacancy centers (VSi−) in SiC via radio frequency (RF) excitation offers a promising approach to realizing room temperature quantum sensors. Conventional excitation schemes with a single RF antenna have limited control over the polarization of incident RF radiation. Here, we demonstrate how an optical setup operating in the continuous wave can be modified for polarization control, which can be leveraged for optical detection and control of multi-RF photon magnetic resonances occurring in VSi− defects in 4H–SiC. The difference in the RF power dependency of the multiphoton peaks in the Optically Detected Magnetic Resonance (ODMR) spectra with that of the Zero Field Split peak hints at the dissimilar origin of the peaks. These resonances are also detected in the presence of an external static magnetic field. To understand their origin, an additional RF source is introduced in the experimental setup that allows control of the polarization of the RF excitation at the defect site. The dependence of the zero field ODMR contrast relating to these resonances on the RF polarization indicates strong correlation between these parameters, which can be manipulated for a lock-in detection technique for RF-frequency.