Power Coupling and Modal Analysis of SPR based Gap Waveguides for Optical Sensing Applications

In this work, the modal analysis and power coupling analysis of gap plasmon waveguides for use in optical sensing applications is presented. The structure consists of Silver (Ag) metallic waveguides separated by a very small gap distance in the range of less than 100nm on glass substrate. The power coupling analysis is carried out at 1550nm for variations in numerical aperture (NA) of optical source. The modes are coupled to the air gap and results in 4.8% to 12.17% of optical power coupling by using high numerical aperture optical beam.