a Schematic of the nitrogen-vacancy-Y3Fe5O12/Pt device to establish a coherent coupling between propagating spin waves and the nitrogen vacancy (NV) spin. b Scanning electron microscope image of a prepared device with a patterned Y3Fe5O12 (YIG) waveguide and two coplanar waveguides (CPWs) to excite propagating surface spin waves. An electric current flowing through the Pt layer is employed to generated spin currents, enabling control of magnetic damping and amplitude of the excited spin waves. G and S represent ground and signal lines, respectively. The scale bar corresponds to 50 µm. c Spin-wave excitation spectra obtained by Fourier transformation of the microwave fields generated by the CPW. d Normalized photoluminescence intensity of the NV center as a function of Bext and microwave frequency f. The two black straight lines correspond to the NV electron spin resonance transitions and the four white dash lines correspond to the field dispersion curves of propagating surface spin wave modes with characteristic wavevectors of k1, k2, k3, and k4.