  Dipolar magnon-magnon coupling has long been predicted in nano-patterned
artificial spin systems. However, observation of such phenomena and related
collective spin-wave signatures have until recently proved elusive or limited
to low-power edge-modes which are difficult to measure experimentally. Here we
describe the requisite conditions for dipolar mode-hybridisation, how it may be
controlled, why it was not observed earlier and how strong coupling may occur
between nanomagnet bulk-modes. We experimentally investigate four
nano-patterned artificial spin system geometries: `chevron' arrays, `square',
`staircase' and `brickwork' artificial spin ices. We observe significant
dynamic dipolar-coupling in all systems with relative coupling strengths and
avoided-crossing gaps supported by micromagnetic-simulation results. We
demonstrate reconfigurable mode-hybridisation regimes in each system via
microstate control, and in doing so elucidate the underlying dynamics governing
dynamic dipolar-coupling with implications across reconfigurable magnonics. We
demonstrate that confinement of the bulk-modes via edge effects play a critical
role in dipolar hybridised-modes, and treating nanoislands as a coherently
precessing macro-spins or standing spin-waves are insufficient to capture
experimentally-observed coupling phenomena. Finally, we present a
parameter-space search detailing how coupling strength may be tuned via
nanofabrication-dimensions and material properties.
