LAUSR

This work demonstrates a membrane-based chiral plasmonic metamaterial with two plasmonic absorption bands which can be used for broadband surface-enhanced infrared absorption (SEIRA) and vibrational circular dichroism (VCD) sensing in the spectral range ∼1000–4000 cm–1 (SEIRA) and ∼2000–4000 cm–1 (VCD). Based on finite-difference time-domain simulations, the chiral plasmonic response was optimized for enhancement at around 3200 cm–1. Accordingly, the chiral cross-slit array was adjusted for application in conventional transmission measurement setups and covers an area of 1 mm2. Polyethylene was used as a model analyte to simulate the SEIRA broadband response and the results were compared with octadecanethiol measurements due to their spectral similarity. Signal enhancement was observed from 3000 cm–1 down to 1400 cm–1 by tuning the polarization of the incoming radiation. Due to the inherent chirality of the design, a strong VCD absorbance of 0.83 at ∼3500 cm–1 could be observed for the unloaded substrate....