Schematic drawing of a cavity with embedded quantum system.  The quantum system is coupled to the cavity photons and can be probed by measuring the cavity transmission or reflection.

Nature Review Article on Hybrid Quantum Systems

Superconductor–semiconductor hybrid-circuit quantum electrodynamics
G. Burkard, M. J. Gullans, X. Mi, and J. R. Petta
Nature Rev. Phys. 2, 129 (2020).