Reusable wafer-scale plasmonic chiral substrates for sensing applications

Three dimensional chiral plasmonic nanostructures exhibit large circular dichroism which can be altered by changing the geometry, size of nanostructures and the plasmonic material. Here, we have explored the possibility of using chiral nanostructured films as reusable substrates for sensing the presence of analytes. These wafer-scale fabricated plasmonic substrates show a strong sensitivity to change in the refractive index of the surrounding medium. Crucially, the chiral plasmonic films retain their circular dichroism once the analyte is completely washed off and dried. This methodology of sensing offers a simple solution to the difficulties associated with expensive and time-consuming fabrication steps and device-to-device variability issues often associated with nanoplasmonic sensing devices.