Hybrid Magnetoplasmonic Crystals Boost the Performance of Nanohole Arrays as Plasmonic Sensors

We present here a theoretical study that shows how the use of hybrid magnetoplasmonic crystals comprising both ferromagnetic and noble metals leads to a large enhancement of the performance of nanohole arrays as plasmonic sensors. In particular, we propose using Au−Co−Au films perforated with a periodic array of subwavelength holes as transducers in magnetooptical surface-plasmon-resonance sensors, where the sensing principle is based on measurements of the transverse magnetooptical Kerr effect. We demonstrate that this detection scheme may result in bulk figures of merit that are 2 orders of magnitude larger than those of any other type of plasmonic sensor. The sensing strategy put forward here can make use of the different advantages of nanohole-based plasmonic sensors such as miniaturization, multiplexing, and its combination with microfluidics.