Enabling enhanced emission and low-threshold lasing of organic molecules using special Fano resonances of macroscopic photonic crystals

TLDR

Light–matter interactions can be dramatically altered in optical cavities, yet incorporating organic molecules into the typically inorganic nanostructured cavities that enable such effects remains challenging. The authors introduce an optofluidic platform that suspends organic molecules in solution on a photonic crystal surface, enabling macroscopic Fano resonances for strong, tunable light–molecule interactions. They develop a theoretical framework and compare it rigorously with experiments, demonstrating dramatic spectral and angular enhancement of emission. The enhancement mechanisms enable lasing from a 100‑nm thin layer of diluted organic molecules with a substantially reduced threshold, promising for organic LEDs and sensing.

Abstract

The nature of light interaction with matter can be dramatically altered in optical cavities, often inducing nonclassical behavior. In solid-state systems, excitons need to be spatially incorporated within nanostructured cavities to achieve such behavior. Although fascinating phenomena have been observed with inorganic nanostructures, the incorporation of organic molecules into the typically inorganic cavity is more challenging. Here, we present a unique optofluidic platform comprising organic molecules in solution suspended on a photonic crystal surface, which supports macroscopic Fano resonances and allows strong and tunable interactions with the molecules anywhere along the surface. We develop a theoretical framework of this system and present a rigorous comparison with experimental measurements, showing dramatic spectral and angular enhancement of emission. We then demonstrate that these enhancement mechanisms enable lasing of only a 100-nm thin layer of diluted solution of organic molecules with substantially reduced threshold intensity, which has important implications for organic light-emitting devices and molecular sensing.