Ultrasensitive biosensors using Fano resonances in double-layer gold nanostructures

Nanostructure-based sensors are capable of sensitive and label-free detection for biomedical applications. However, plasmonic sensors capable of multiplexed highly sensitive detection with high-throughput and low-cost fabrication techniques are desirable. Here, we utilize a thermal-annealed template-stripping method to fabricate large-area double-layer gold nanostructures on polymer films with low cost and high SPR sensitivities. We found that a transverse magnetic-polarized wave in these gold nanostructures generated sharp and asymmetric Fano resonances in transmission spectra. The full width at half-maximum bandwidth was 3.84 nm and the wavelength sensitivity was 560 nm/RIU. In addition, it has a higher intensity sensitivity up to 44381 %/RIU.