Conclusion
Plasmonic sensors based on MIM WGs are exceedingly attractive due to their small footprint and can offer extremely high sensitivity which cannot be obtained with conventional dielectric WG sensors. The triumph of such devices remains in the straightforward, accurate, less complex, low-cost fabrication and its compatibility with the existing platforms. Moreover, flexible sensor designs are required where minor variations in the geometric parameters due to fabrication imperfections should not deteriorate its sensing performance. Hence, Dr. Butt, the author of this paper believes that the plasmonic mode converter proposed by Ono M et al. at NTT is valuable for the realization of such a plasmonic WG structure, however, it is still in its infancy and entails a long way to find alternate ways to ensure the reproducibility of such devices with low technology demand.