An efficient and ultra-broadband unidirectional optical coupler for wide incidence angles

An efficient and unidirectional optical coupling scheme for metal-dielectric-metal (MDM) waveguides with wide-angle and ultra-broadband efficiency is proposed and demonstrated. Based on joint effects of the plasmonic critical angle phenomenon (PCA), the zero-order grating resonance, and the first-order Fabry Perot (FP) resonance of the MDM waveguide, the illuminated light could be efficiently coupled into MDM plasmonic waveguide with angular-full-width-half-maximum (AFWHM) widen to 50 over a broad wavelength range 750-1000 nm. The operation principle and performance of the structure are clarified and theoretically illustrated. (C) 2016 Elsevier B.V. All rights reserved.high resolution earth observation system major special project Youth Innovation Foundation of China [GFZX04060103]SCI(E)EIARTICLEwangzhonghua_dr@163.com1-537