AWG-Driven High-Frequency Optically Detected Magnetic Resonance for NV Quantum Sensing*

High-fidelity of quantum control of spin states is paramount for magnetic resonance spectroscopy and quantum sensing. Pulse shaping is promising to improve the fidelity of spin state manipulation. However, the application of pulse shaping to high-frequency ESR and related techniques is still limited due to technical challenges.   

Within this work, we discuss our recent development of a 115/230 GHz optically detected magnetic resonance (ODMR) spectrometer driven by arbitrary waveform generator (AWG) for NV quantum sensing applications [1,2]. Our experimental setup consists of an IQ modulated ~9 GHz synthesizer using an AWG. ~9 GHz microwaves are sent through a frequency multiplication chain (FMC) to obtain a shaped pulse at 115/230 GHz. Due to the highly nonlinear response of FMC, the amplitude modulation of 115/230 GHz microwave is highly challenging. We have recently overcome this challenge by implementing closed-loop feedback control. Shaped pulses can be used for selective excitation and efficient population inversion in high-frequency ESR/ODMR. We also discuss applications of AWG-driven high-frequency ODMR for NV sensing.