Focusing and demultiplexing of an in-plane hybrid plasmonic mode based on the planar concave grating

In this paper we present the focusing and demultiplexing of an in-plane propagating hybrid plasmonic mode based on the planar concave grating structure. The grating system is designed based on the Rowland mounting, where the Rowland circle provides the focusing ability while the grating itself provides the dispersion. About 30 nm's resolution is achieved in the current design and can be further improved by adjusting the grating parameters. The in-plane design makes the device free of the surface plasmon polariton (SPP) coupling issues and is favorable for planar integrated circuits (PICs). Furthermore, the grating system with linear dispersion offers convenience in designing wavelength division multiplexing (WDM) elements.