[Paper Review] Multi-wavelength Spin Dynamics of Defects in Hexagonal Boron Nitride

Ivan Zhigulin, Nicholas P. Sloane+4 more|arXiv (Cornell University)|Feb 5, 2026

Graphene research and applications0 citations

TL;DR

The paper investigates how excitation wavelength influences spin-dependent fluorescence and spin dynamics of defects in hexagonal boron nitride, revealing a threefold improvement in ODMR contrast and magnetic field sensitivity.

ABSTRACT

Optically addressable solid-state spin defects are essential platforms for quantum sensing and information processing. Recently, single spin defects with combined S = 1 and S = 1/2 spin transitions were discovered in hexagonal boron nitride (hBN). In this work we unveil their excitation dynamics. In particular, we study the effects of the excitation wavelength on the spin-dependent fluorescence and the spin dynamics of these peculiar quantum spin defects. We find that changing the excitation wavelength leads to a threefold enhancement in both the optically detected magnetic resonance (ODMR) contrast and the corresponding magnetic field sensitivity. In addition, we find that the excitation wavelength has a strong impact on the photodynamics of spin complex emitters. Our work presents valuable insights to the mechanistic understanding of spin complex emitters in hBN and highlights the importance of excitation wavelength for optimising their performance in quantum sensing and quantum technologies.

Motivation & Objective

• Motivate the use of optically addressable spin defects in hBN for quantum sensing and information processing.
• Investigate how different excitation wavelengths affect spin-dependent fluorescence and spin dynamics of hBN defects labeled as spin complex emitters.
• Elucidate mechanistic insights into spin complex emitters and their photodynamics under varied excitation.
• Assess how excitation wavelength can optimize performance for quantum sensing and technologies.

Proposed method

• Study spin-dependent fluorescence and ODMR under multiple excitation wavelengths.
• Characterize spin dynamics of defects with S = 1 and S = 1/2 transitions in hBN.
• Analyze how excitation wavelength modulates photodynamics of spin complex emitters.
• Quantify enhancement in ODMR contrast and magnetic field sensitivity with wavelength changes.

Experimental results

Research questions

• RQ1 How does the excitation wavelength affect ODMR contrast in hexagonal boron nitride spin defects?
• RQ2 What is the impact of excitation wavelength on the spin dynamics of defects with combined S = 1 and S = 1/2 transitions?
• RQ3 How do excitation wavelengths influence the photodynamics of spin complex emitters in hBN?
• RQ4 Can tuning the excitation wavelength optimize quantum sensing performance using hBN defects?

Key findings

• Changing the excitation wavelength leads to a threefold enhancement in ODMR contrast.
• The corresponding magnetic field sensitivity is also enhanced by the same factor.
• The excitation wavelength strongly impacts the photodynamics of spin complex emitters.
• The work provides mechanistic insights into spin complex emitters in hBN and the role of excitation in optimization.
• The results highlight the importance of excitation wavelength for quantum sensing applications using hBN defects.