Ultracompact plasmonic loop–stub notch filter and sensor

A new nanoplasmonic notch filter and a biosensor, based on the loop–stub configuration, are proposed and studied. Our finite-difference time-domain simulations reveal that the resonant mode of the proposed structure can be easily controlled by varying the width of the horizontal branch of the loop–stub structure. The proposed plasmonic biosensor has a high sensitivity and a remarkably large figure-of-merit. Besides the advantages of easy fabrication, the device has a compact size of only a few hundred nanometers in width and length. The special features of the proposed structure and the device concept introduced in this work are applicable in the realization of various integrated components for the development of plasmonic biosensors.