Enhancement and Inhibition of Spontaneous Photon Emission by Resonant Silicon Nanoantennas

TL;DR

This paper demonstrates that silicon nanoantennas can both enhance and inhibit spontaneous photon emission from fluorescent molecules at room temperature, offering a low-loss alternative to plasmonic materials for nanoscale optical control.

Contribution

It introduces the use of silicon nanoantennas to manipulate photon emission dynamics, showing both enhancement and inhibition effects at room temperature, which was not possible with noble metals.

Findings

Increased or decreased decay rates by up to 15%.

Enhanced photon collection efficiency by up to 85%.

Silicon nanoantennas enable low-loss optical manipulation at the nanoscale.

Abstract

Substituting noble metals for high-index dielectrics has recently been proposed as an alternative strategy in nanophotonics to design broadband optical resonators and circumvent the ohmic losses of plasmonic materials. In this report, we demonstrate that subwavelength silicon nanoantennas can manipulate the photon emission dynamics of fluorescent molecules. In practice, it is showed that dielectric nanoantennas can both increase and decrease the local density of optical states (LDOS) at room temperature, a process that is inaccessible with noble metals at the nanoscale. Using scanning probe microscopy, we analyze quantitatively, in three dimensions, the near-field interaction between a 100 nm fluorescent nanosphere and silicon nanoantennas with diameters ranging between 170 nm and 250 nm. Associated to numerical simulations, these measurements indicate increased or decreased total spontaneous decay rates by up to 15 % and a gain in the collection efficiency of emitted photons by up to 85 %. Our study demonstrates the potential of silicon-based nanoantennas for the low-loss manipulation of solid-state emitters at the nanoscale and at room temperature.