All-Optical Brain Thermometry in Freely Moving Animals
Ilya V. Fedotov, Maxim A. Solotenkov, M. S. Pochechuev, О. И. Ивашкина, S. Ya. Kilin, K. V. Anokhin, А. М. Желтиков
Abstract
We present all-optical high-resolution temperature measurements in the brain of freely behaving mice using an implantable thermometer that integrates a reconnectable two-section fiber-optic probe and a microcrystal of diamond with germanium-vacancy (GeV) centers. The local brain temperature is read out from the photoluminescence spectrum of GeV centers coupled to the guided modes of the optical fiber implanted in a mouse brain. This fiber thermometer is shown to enable brain temperature measurements with an accuracy within 0.15 °C at a level of laser power low enough to keep laser-induced heating of the brain well below 0.1 °C.