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 magneto-optical surface-plasmon-resonance sensors, where the sensing principle is based on measurements of the transverse magneto-optical 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.