Abstract

Atom-like defects in solids are promising building blocks for quantum technologies. Among these, group-IV color centers in diamond are especially attractive because their inversion symmetry supports excellent optical coherence, while their electronic and spin properties remain highly tunable through the local solid-state environment. In this talk, I will discuss how group-IV color centers can be engineered as solid-state quantum nodes by controlling both their optical interface and their spin structure. First, I will show that a resonantly driven germanium-vacancy center can function as an atomic optical antenna that enables the detection and control of nearby dark defects. Second, I will describe ongoing work showing that large strain can reshape the spin-orbital structure of group-IV centers, partially release the electron spin from its usual locking to the defect axis and allow its quantization axis to be modified by an external magnetic field. This strain-engineered regime provides a route toward improved coherence at higher temperature, reduced sensitivity to magnetic-field alignment, enhanced optical cyclicity for spin readout, and more flexible access to nearby nuclear-spin memories. Together, these results illustrate how group-IV color centers can be transformed from passive defects into engineered quantum nodes.