Structured hyperbolic metamaterials for control of spontaneous emission (Conference Presentation)

The control of spontaneous emission via the design of composite materials with engineered electromagnetic properties is important for the development of new faster and brighter sources of illumination with applications ranging from biophysics to quantum optical technologies. In particular, the fabrication of nanostructures leading to broadband enhancement of emission is of great interest. Hyperbolic plasmonic metamaterials have recently emerged as a very flexible platform for this purpose as they provide a high local density of electromagnetic states available for the radiative relaxation of emitters. This is due to their peculiar mode structure governed by both the structural nonlocal response and the dispersion properties. Here, we investigate the modification of the spontaneous emission rate and intensity enhancement of emitters located inside a nanorod-based hyperbolic metamaterial. We experimentally show the coupling of the radiated emission to the waveguided mode of a planar hyperbolic metamaterial with finite thickness. The emitters located inside this planar hyperbolic metamaterial waveguide exhibit an almost 50-fold reduction of the decay rate and 3-fold intensity enhancement of the fluorescence coupled to the mode. We also discuss the effect of nanostructuring the nanorod-based metamaterial on the spontaneous emission properties of emitters located inside it, where suitable designs can lead to further enhancement of the radiative rate and improved light extraction of the emission coupled to the high-wavevector modes of the metamaterial to the far-field, useful for the development of efficient and fast free-space light-emitting devices.