All-Optical Light-Propagation Switching

Miniaturised photonic circuits have been employed in a broad field of fundamental, but also application-oriented research in the recent years. While the harnessing of CMOS fabrication techniques has enabled precise sub-wavelength feature control, the dynamic switching of nano-optical devices often involves additional thermo-optical or electro-optical elements. The high number of processing steps and materials lead to a costly device fabrication and an inherent proneness to the failure of single components. The present contribution demonstrates an all-optical switch utilising two counter-propagating beams to control the in-coupling efficiency of a nano-optical grating. The findings of the fundamental experiment are shown to support the development of a range of applications including all-optical logic gates and non-Hermitian photonic circuits. The demonstrated coupling control enables complexity reduction in integrated photonic circuits and provides a promising approach for a new, streamlined device architecture.