Suppressing Thermal Noise to Sub-Millikelvin Level in a Single-Spin Quantum System Using Realtime Frequency Tracking

Area of Science:

• Quantum sensing
• Nanoscience
• Diamond quantum technologies

Background:

• Single nitrogen-vacancy (NV) centers in diamond are versatile nanoscale sensors for magnetic fields, electric fields, and nuclear spins.
• Low photon detection efficiency in NV centers leads to long sensing times, hindered by electron spin resonance (ESR) frequency fluctuations from thermal noise.
• Suppressing thermal noise is crucial for enhancing NV sensor performance, but traditional methods require complex and costly millikelvin-level thermal control.

Purpose of the Study:

• To analyze real-time thermal drift affecting NV center quantum sensing.
• To develop an active, cost-effective method for stabilizing NV center ESR frequency.
• To improve spin-state readout contrast and overall performance in long-term NV-based experiments.

Main Methods:

• Analysis of real-time thermal drift in single-spin ESR frequency.
• Implementation of an active tracking method to compensate for frequency drift.
• Experimental validation without requiring additional environmental thermal control apparatus.

Main Results:

• Achieved a temperature stabilization effect equivalent to the sub-millikelvin (0.8 mK) level.
• Significantly improved spin-state readout contrast in long-lasting experiments.
• Demonstrated a method that bypasses the need for complex, costly cryogenic systems.

Conclusions:

• The developed active tracking method effectively suppresses thermal noise and drift in NV center sensing.
• This technique offers a practical and broadly applicable solution for enhancing NV-based quantum sensing performance.
• The approach shows potential for expansion into other nanoscale quantum sensing applications.