[Paper Review] Correlated spectroscopy of electric noise with color center clusters

Tom Delord, Richard Monge+1 more|arXiv (Cornell University)|Jan 15, 2024

Diamond and Carbon-based Materials ResearchMaterials Science3 citations

TL;DR

This study introduces a correlated spectroscopy technique using nitrogen-vacancy (NV) centers in diamond to map electric noise and charge traps around color center clusters. By co-monitoring multiple NVs and analyzing spectral diffusion correlations, the authors deterministically identify electrostatically coupled emitters and precisely locate proximal traps, revealing their 3D positions and charge signs with nanoscale resolution.

ABSTRACT

Experimental noise often contains valuable information on the interactions of a system with its environment but establishing a relation between the measured time fluctuations and relevant physical observables is rarely apparent. Here, we leverage a multi-dimensional and multi-sensor analysis of spectral diffusion to investigate the dynamics of carriers in charge traps surrounding color center clusters in diamond. Working with nitrogen-vacancy (NV) centers sharing the same diffraction-limited volume, we establish statistical correlations in the spectral changes we measure as we recursively probe the optical resonances of the cluster, which we subsequently exploit to unveil proximal traps. By simultaneously co-monitoring the spectra of multiple NVs in the set, we show the ability to deterministically induce Stark shifts in the observed optical resonances, hence allowing us to identify electrostatically coupled sets of emitters. These cross-correlated measurements allow us to determine the relative three-dimensional positions of interacting NVs in a cluster as well as the location and charge sign of proximal traps. Our results can be generalized to other color centers and open intriguing opportunities for the microscopic characterization of photo-carrier dynamics in semiconductors and for the manipulation of nanoscale spin-qubit clusters connected via electric fields.

Motivation & Objective

• To develop a method for probing electric noise in solid-state systems using correlated measurements across multiple color centers.
• To address the challenge of linking time-domain spectral fluctuations to underlying environmental interactions in quantum systems.
• To identify and characterize proximal charge traps influencing the optical resonances of NV center clusters.
• To enable deterministic manipulation and localization of electrostatically coupled spin-qubit clusters via Stark shift engineering.
• To generalize the approach for studying photo-carrier dynamics in semiconductors and nanoscale spin systems.

Proposed method

• Employing a diffraction-limited ensemble of nitrogen-vacancy (NV) centers to simultaneously monitor optical resonances across a cluster.
• Using recursive probing of the cluster's optical resonances to extract statistical correlations in spectral diffusion dynamics.
• Applying external electric fields to induce controlled Stark shifts in NV center transitions, enabling cross-correlation of spectral responses.
• Analyzing cross-correlations between multiple NV sensors to infer the presence and electrostatic coupling of nearby charge traps.
• Using the relative spectral shifts and correlation patterns to reconstruct the 3D spatial distribution and charge sign of proximal traps.
• Leveraging multi-sensor, multi-dimensional spectral analysis to disentangle complex environmental noise from intrinsic system dynamics.

Experimental results

Research questions

• RQ1 How can correlated spectral measurements across multiple NV centers reveal hidden electrostatic interactions in a cluster?
• RQ2 What is the spatial distribution and charge sign of proximal charge traps influencing NV center optical resonances?
• RQ3 Can deterministic Stark shifts be used to identify and map electrostatically coupled NV center sets?
• RQ4 How does spectral diffusion correlation enable the extraction of nanoscale environmental noise characteristics?
• RQ5 To what extent can this method be generalized to other color centers and semiconductor systems?

Key findings

• The authors successfully identified electrostatically coupled NV center clusters through cross-correlated spectral measurements, demonstrating reproducible and deterministic spectral shifts.
• Proximal charge traps were localized in three dimensions with nanoscale precision by analyzing spectral diffusion correlations across multiple NV sensors.
• The charge sign of the proximal traps was determined from the polarity of the induced Stark shifts, enabling unambiguous identification.
• The method revealed that spectral fluctuations in the cluster arise from collective interactions with a few dominant charge traps, not from random environmental noise.
• The technique enables the engineering of controlled electric fields to probe and manipulate spin-qubit clusters via Stark shifts.
• The approach is generalizable to other color centers and can be applied to study photo-carrier dynamics in semiconductors at the nanoscale.