All‐Optical Sensing of Pressure and Temperature With Magnesium‐Vacancy Color Centers in Diamond

ABSTRACT We provide the first characterization of Magnesium–Vacancy (MgV) color centers under hydrostatic high‐pressure conditions. The luminescent defects were fabricated upon ion implantation into a diamond anvil, which was subsequently assembled into a Diamond Anvil Cell (DAC). The photoluminescence study, performed at 87 K, reveals a blueshift of the Zero‐Phonon Line (ZPL) induced by increasing compressive stress, with a slope of 2.1 meV/GPa. A theoretical model of the electronic level structure of the center has been developed to support the experimental findings, showing good compatibility with the measured shift. In addition, the optical response of centers was investigated upon temperature variations.The results obtained further confirm the previously reported temperature‐induced shift of the ZPL, which undergoes a redshift during cool down, in the opposite direction with respect to that observed in other color centers explored under changing temperature. The theoretical calculations reproduce this temperature dependence as well, complementing the characterization of centers as temperature sensors. These results are discussed in relation to existing studies on centers, expanding the understanding of this recently discovered quantum emitter and unlocking its employment as an all‐optical sensor of pressure and temperature.