Robust inverse design of non-periodic Bloch surface wave sensors

Abstract

One-dimensional photonic crystals supporting Bloch surface waves (BSWs) have emerged as highly sensitive platforms for label-free refractometric sensing. However, the practical performance of these sensors is limited by their vulnerability to fabrication-induced thickness variations. In this Letter, we address this challenge by introducing a robust inverse design framework based on multi-objective genetic optimization. This framework jointly maximizes intensity sensitivity and resilience against manufacturing errors, demonstrating that non-periodic multilayers achieve inherently superior sensitivity-robustness trade-offs, with a pronounced gain in device resilience over conventional periodic designs. By analyzing the optimized designs, we uncover an intrinsic compensation mechanism that physically governs the trade-off and effectively stabilizes the sensor response against structural perturbations. By unlocking the expanded design space of non-periodic multilayers, our optimization strategy paves the way for the practical realization of next-generation BSW sensors.