Direct comparison of the performance of Bloch surface wave and surface plasmon polariton sensors

We report on the direct experimental comparison of the sensitivity and figure of merit of biosensors based either on surface plasmon polaritons on metal layers or on Bloch surface waves on one dimensional photonic crystals. The comparison was carried out by making use of a commercial surface plasmon resonance platform that was slightly adapted for these experiments. Although the experimental conditions are not optimized for Bloch surface waves, our experiments demonstrate that both types of biosensors show a similar figure of merit for biochips deposited on low cost molded plastic substrates. For glass substrates with better optical quality, the increased homogeneity of the photonic crystals results in the Bloch surface wave sensors outperforming the surface plasmon polariton sensors by a factor 1.7 in terms of figure of merit. Considerations on the illumination bandwidth indicate options to further increase such a factor.