Enhanced Sugar Sensing via a Fano Resonance Terahertz Metasurface with a Metallic Cross-shaped Hole Array

In this paper, we developed a spectral biochemical sensor by introducing new electric resonance meta-atoms to generate Fano resonance, thereby enhancing the sensing performance. Simulations explained the enhancement mechanism, followed by the fabrication of the sensor using femtosecond laser direct writing technology to sculpt large cross-shaped lines around a pre-existing array of small cross-shaped holes. The sensing functionality of the metasurface was verified through sugar detection tests, where we detected erythritol, glucose, and lactose, achieving high sensitivity (4.88 GHz/mM) and a low detection limit (0.82 mM) for lactose. This study offers an innovative method for the design, fabrication, and application of high-performance terahertz sensors.