Study on Diamond NV Centers Excited by Green Light Emission from Upconversion Luminescence

The NV center in diamonds has been widely employed in quantum sensing, quantum computing, and bioimaging due to its controllable ground-state spin, detectable magnetic resonance, excellent photostability, favorable biocompatibility, and chemical inertness. However, conventional excitation using 532 nm green light still exhibits certain limitations in practical applications. To address this, we propose a novel NV center excitation method based on the upconversion of near-infrared light to green emission. Through the synthesis of molybdenum-doped NaYF₄: 20% Yb³⁺, 1.5% Er³⁺ upconversion materials, efficient excitation of NV centers has been achieved. Both UC-LED luminescence spectroscopy and ODMR measurements confirm that the green light generated via the upconversion process exhibits sufficient intensity to effectively excite NV centers. Meanwhile, the characteristic sharp emission peaks of rare-earth upconversion materials eliminate the need for optical filters, facilitating device miniaturization, and a miniaturized UC-LED sensor has been developed.