Spin number dependent dissipative coupling strength

Abstract

A system consisting of a yttrium iron garnet (YIG) sphere coupled to a 1D circular-rectangular cavity is tuned between level repulsion and attraction by rotating the angular position of the YIG sphere within the cavity. The dominance of coherent or dissipative coupling mechanisms was determined, and the coupling strength was deduced by fitting the transmission spectra. By changing the diameter of the YIG sphere from 0.5 mm to 0.3 mm and 1.0 mm, we confirm that the N scaling of coherent coupling strength is also applicable in dissipative coupling. A large YIG sphere leads to an enhanced coupling strength that is useful for information processing. Alternatively, a small YIG sphere results in a narrow transition regime, which may be helpful for identifying the dissipative coupling dominated regime and providing insight into the physical origin of dissipative coupling.