A Self-driving Rb-Xe Spin Oscillator

A self-driving Rb-Xe spin oscillator is demonstrated in theory and experiment. The original photo-detected signal of atom spin oscillation is amplified, phase-shifted and sent back to drive the spins itself coherently. By fine tuning the driving strength and phase, a self-sustaining spin oscillation signal with zero frequency shift is obtained. The effective coherence time is extremely prolonged beyond the intrinsic coherence time of noble gas atomic spins, forming a spin oscillator. Spectral analysis indicates that a frequency resolution of 9 nHz is achieved, which can enhance the sensitivity of magnetic field and angular velocity sensing. Allan deviation analysis shows that the spin oscillator can operate in continuous wave mode like a maser or laser, providing an ideal tool for long term precision measurement physics research.