Selective Temperature Sensing in Nanodiamonds Using Dressed States

Techniques for temperature sensing at sub-micron length scales are an area of ongoing investigation, with applications ranging from characterizing heat dissipation in electronic devices to cellular metabolism. The nitrogen-vacancy (NV) center in diamond is a system with the potential to meet these needs, but is often limited by its overwhelming sensitivity to magnetic fields. Here, we demonstrate a method for suppressing the sensitivity to magnetic fields on-demand by a factor of seven without modifying the NV center, resulting in a technique that is selectively sensitive to temperature changes^[1]. To achieve this, we combine optically detected magnetic resonance (ODMR) with an additional megahertz-range driving field to engineer dressed states for the NV center, enabling us to tailor its Hamiltonian to our specific sensing requirements. While this approach has been used elsewhere for enhancing temperature sensitivity in bulk diamonds^[2], we show that it can be applied to nanodiamonds, which are easier to integrate with existing devices^[3] but suffer from broader linewidths, shorter coherence times, and random orientations. We demonstrate a greatly reduced Zeeman shift of ~1 MHz over a 3G range for our dressed state approach, compared to ~7 MHz for the bare state, and characterize the nature of the dressed states. By combining numerical simulations with our experimental data, we explore the limitations and prospects of enhanced temperature sensing in nanodiamonds with further material improvements.<br/><br/>[1] Beaver, N.M. and Stevenson, P., 2024. Selective temperature sensing in nanodiamonds using dressed states. https://arxiv.org/abs/2406.04522<br/>[2] Tabuchi, H., et al., 2023. Temperature sensing with RF-dressed states of nitrogen-vacancy centers in diamond. Journal of Applied Physics, 133, no.2, pp. 024401-1 to 024401-8. https://doi.org/10.1063/5.0129706<br/>[3] Foy, C., et al., 2020. Wide-field magnetic field and temperature imaging using nanoscale quantum sensors. ACS Applied Materials & Interfaces, 12, no.23, pp. 26525 to 26533. https://doi.org/10.1021/acsami.0c01545