[Paper Review] Quantum coherence control at near 1000 K

Gang‐Qin Liu, Xi Feng+3 more|arXiv (Cornell University)|Oct 31, 2018

Diamond and Carbon-based Materials Research32 references19 citations

TL;DR

This study demonstrates room-temperature initialization and readout of nitrogen-vacancy (NV) center electron spins in nanodiamonds, followed by high-temperature control up to 1000 K using pulsed laser heating and rapid thermal diffusion on amorphous carbon films. The method enables observation of the magnetic phase transition in a single nickel nanoparticle at ~615 K, establishing a platform for nano-thermometry and nano-magnetometry in extreme thermal environments.

ABSTRACT

Quantum coherence control usually requires extremely low temperature environments. Even for spins in diamond, a remarkable exception, the coherence signal is lost as temperature approaches 700 K. Here we demonstrate quantum coherence control of the electron spins of nitrogen-vacancy centers in nanodiamonds at temperatures near 1000 K. The scheme is based on initialization and readout of the spins at room temperature and control at high temperature, which is enabled by pulse laser heating and rapid diffusion cooling of nanodiamonds on amorphous carbon films. Using high-temperature spin control, we observe the magnetic phase transition of a single nickel nanoparticle at about 615 K. This work enables nano-thermometry and nano-magnetometry in the high-temperature regime.

Motivation & Objective

• To extend quantum coherence control of NV centers in nanodiamonds beyond the typical 700 K limit.
• To enable high-temperature spin manipulation for applications in nano-thermometry and nano-magnetometry.
• To overcome thermal decoherence in electron spins at elevated temperatures using a novel thermal management scheme.
• To observe a magnetic phase transition in a single nickel nanoparticle at high temperature using NV center sensing.
• To demonstrate room-temperature initialization and readout coupled with high-temperature control in a single nanoscale system.

Proposed method

• Utilizes pulsed laser heating to rapidly elevate the temperature of nanodiamonds on amorphous carbon films to near 1000 K.
• Employs rapid thermal diffusion through the amorphous carbon substrate to cool the nanodiamonds quickly after heating.
• Performs room-temperature initialization and readout of NV center electron spins to preserve quantum coherence.
• Applies high-temperature spin control protocols to maintain coherence during thermal excursions.
• Uses the NV center's spin-dependent fluorescence to detect magnetic responses from nearby nanoparticles.
• Employs a custom micro-thermal setup to enable precise temperature control and optical access.

Experimental results

Research questions

• RQ1 Can quantum coherence of NV centers in nanodiamonds be preserved and controlled at temperatures approaching 1000 K?
• RQ2 What thermal management strategy enables high-temperature spin control without decoherence?
• RQ3 Can a single NV center detect magnetic phase transitions in a nanoparticle at elevated temperatures?
• RQ4 Is it feasible to perform room-temperature initialization and readout while maintaining high-temperature control?
• RQ5 Can this system enable nano-scale thermometry and magnetometry in extreme thermal environments?

Key findings

• Quantum coherence of NV centers in nanodiamonds is successfully maintained and controlled at temperatures up to 1000 K.
• The system enables detection of the magnetic phase transition in a single nickel nanoparticle at approximately 615 K.
• Room-temperature initialization and readout of NV spins are achieved while high-temperature control is performed via pulsed laser heating.
• Rapid thermal diffusion through amorphous carbon films prevents thermal damage and preserves spin coherence during heating cycles.
• The method enables high-fidelity spin control and sensing in extreme thermal conditions, extending the operational window of NV-based sensors.
• The approach demonstrates a viable pathway for nano-thermometry and nano-magnetometry in high-temperature environments.