Maximum electromagnetic local density of states via material structuring

Abstract The electromagnetic local density of states (LDOS) is crucial to many aspects photonics engineering, from enhancing emission photon sources radiative heat transfer and photovoltaics. We present a framework for evaluating upper bounds on the LDOS in structured media that can handle arbitrary bandwidths accounts critical wave scattering effects. are solely determined by bandwidth, material susceptibility, device footprint, with no assumptions geometry. derive an analytical expression maximum consistent conservation energy across entire design domain, which upon benchmarking topology-optimized structures shown be nearly tight large devices. Novel scaling laws enhancement found: saturate finite value increasing susceptibility scale as quartic root bandwidth semi-infinite made lossy materials, direct implications selection applications.