Quantum Photothermal Self‐Monitoring Fiber Probes for In Vivo Photothermal Therapy

ABSTRACT The photothermal properties of diamond nitrogen‐vacancy (NV) centers enable simultaneous fluorescence emission and localized heating, yet conventional free‐space quantum systems suffer from limited photothermal efficiency (typically<4°C/mW) and inadequate microwave integration (large in size). We developed a miniaturized quantum photothermal fiber probe utilizing a novel metal/polymer/glass composite optoelectronic fiber that simultaneously guides both lightwave and microwave radiation (at GHz). By integrating a micron‐scale diamond at the fiber tip, the probe achieves enhanced photothermal conversion (13°C/mW, 25°C–120°C range) while providing real‐time self‐monitoring through temperature‐dependent zero‐field splitting measurements with 0.2°C thermal resolution at the micrometer scale. This mass‐producible platform represents a new class of biocompatible quantum sensors combining high thermal efficiency and precise temperature feedback, as demonstrated by successful promotion of in vivo spinal cord injury repair through controlled thermal stimulation.