In this dissertation, the use of on-chip superconducting (SC) resonators as a probe of spin-photon interactions as well as other superconducting phenomena will be presented. In particular, coherent Rabi oscillations are demonstrated for a spin s = 1/2 ensemble in an ESR (Electron Spin Resonance) cavity as well as coherent multiphoton excitations. Applying techniques from the classical ESR measurements to an on-chip resonator is effectively shrinking the cavity volume and increasing vacuum field density. This in turn can greatly increase the sensitivity creating the possibility of probing the quantum to classical transition for spin-photon interactions. Additionally, an on-chip cavity provides the possibility of on-chip ESR measurements to be performed in a dilution refrigerator.

Furthermore, progress has been made toward on-chip ESR type measurements. A highly sensitive heterodyne measurement setup has been developed, providing the capability of detecting signals as small as -125 dBm. Under the right conditions this setup may be able to detect single photons. To perform an on-chip ESR measurement, precise placement of the spin system at an anti-node of the magnetic field is required. For this, a technique for spin ensemble placement with micron scale precision is developed.

Finally, performing ESR measurements requires the application of a (sometimes large) static field. Even a very small static field and can easily create vortices in a superconducting thin film when applied normal to the film plane. A precise alignment procedure is developed allowing for the operation of on-chip SC resonators to operate with an in-plane field up to 1 Tesla. This led to the first successful field-dependent observation of the nonlinear Meissner effect.