Photoluminescence lifetime engineering via organic resonant films with molecular aggregates.

Manipulating the spontaneous emission rate of fluorophores is vital in creating bright incoherent illumination for optical sensing and imaging, as well as fast single-photon sources for quantum technology applications. This can be done via increasing the Purcell effect by using non-monolithic optical nanocavities; however, achieving the desired performance is challenging due to difficulties in fabrication, precise positioning, and frequency tuning of cavity-emitter coupling. Here, we demonstrate a simple approach to achieve a wavelength-dependent photoluminescence (PL) lifetime modification using monolithic organic molecular aggregates films. These single monolithic organic films are designed to have a Lorentzian dispersion, including epsilon-near-zero (ENZ) and epsilon-near-pole (ENP) spectral regions with increased and decreased photonic density of states, respectively. This dispersion leads to enhanced and depressed PL decay rates at different wavelengths. Both time-resolved photoluminescence (TRPL) and fluorescence lifetime imaging microscopy (FLIM) measurements are implemented to verify the validity of this approach. This approach offers a promising way to design dual-functional optical sources for a variety of applications, including bioimaging, sensing, data communications, and quantum photonics applications.