Phonon-assisted upconversion photoluminescence of quantum emitters

Quantum emitters are widely used in quantum networks, quantum information processing, and quantum sensing due to their excellent optical properties. Compared with Stokes excitation, quantum emitters under anti-Stokes excitation exhibit better performance. In addition to laser cooling and nanoscale thermometry, anti-Stokes excitation can improve the coherence of single-photon sources for advanced quantum technologies. In this review, we follow the recent advances in phonon-assisted upconversion photoluminescence of quantum emitters and discuss the upconversion mechanisms, applications, and prospects for quantum emitters with anti-Stokes excitation.