Multilayer hyperbolic metamaterials and their applications in controlling spontaneous light emission

D. Lu, L. Ferrari, J.J. Kan, E.E. Fullerton, Z. Liu
University of California, San Diego, US

Keywords: metamaterials, plasmonics, time-resolved photoluminescence

Summary:

Recent advances in plasmonics enable the dramatic manipulation of light emitters by controlling spontaneous recombination rates or radiative intensity. The approach to control light emission process inherently relies on the alignment of surface plasmon resonances with emission wavelengths. However, such alignment is available only for a few narrow bands of frequency due to the limited plasmonic materials existing in nature. Hyperbolic metamaterials (HMMs), nanoscale materials with tunable hyperbolic dispersion relations, offer a larger plasmonic density of states (DOS) at desired wavelengths for SE rate enhancement. However, the Purcell factor and the radiative power have remained low due to the difficulties in fabricating multilayers at deep subwavelength scales, and the non-radiative plasmonic modes in uniform HMMs. In this work, we describe nanopatterned HMMs made of metal-dielectric multilayers for controlling the SE process. A systematic study of the different pattern periods results in a 76-fold rate enhancement and ~80-fold intensity enhancement simultaneously in experiment. The experimental results are quantitatively explained using a dynamic Lorentzian model in the time domain. The nanopatterned multilayer HMMs exhibit superior plasmonic properties over pure metal structures for potential applications in biosensing and imaging, surface-enhanced Raman spectroscopy, and light-emitting devices.