Angle-tunable polymeric photonic diode with 1D-photonic crystal for enhanced light control

Abstract

Integrated optical circuits depend on optical diodes for passive nonreciprocal light transmission. The realization of optical diode action remains a significant challenge in nanophotonics, with conventional approaches often relying on non-compact and expensive magneto and electro-optic isolators. This work presents an all-polymeric optical diode based on the principle of asymmetric nonlinear absorption in the nonlinear regime. In contrast to earlier diodes employing this principle, this diode architecture offers a simplified fabrication process, exhibits a compact footprint, and eliminates the need for a liquid phase. The attained optical diode consists of a simple structure employing PEDOT:PSS as a saturable absorber medium and a 1-dimensional polymeric photonic crystal (PhC) structure consisting of gold–carbon core–shell nanostructures (Au@C NS) as a reverse saturable absorber medium. Integration of the active medium into a PhC architecture provides a unique avenue for engineering light–matter interactions, resulting in angle-tunable optical diode activity. This device exhibits all-optical diode action with no phase-matching constraints. Our structure exhibits a nonreciprocity factor of up to ∼12.5 dB, achieved through a facile and cost-effective fabrication method. This promising combination makes this system a potential candidate for developing compact photonic integrated devices.