Optimization for Gold Nanostructure-Based Surface Plasmon Biosensors Using a Microgenetic Algorithm

We present a design method and fabrication technique for enhancing detection sensitivity of gold nanostructure-based surface plasmon resonance (SPR) biosensors. In this case, the nanostructure geometry is arbitrary and the optimal design parameters are determined using a microgenetic algorithm integrated with three-dimensional finite-difference time-domain (3D-FDTD) electromagnetic simulations. The corresponding device is fabricated using hot embossing nanoimprint lithography. Two experimental configurations are used to evaluate the device performance: one is the atomic layer deposition and the other is the protein-protein interaction. The performances of the optimal SPR biosensors are superior to the ones with conventional simple structures under both configurations. The improvements in terms of the fitness function are respectively up to 179% and 128% for the 3D-FDTD simulation and the experimental results. The calculated optical fields indicate that the improvement of the fitness function results from the enhancement of localized SPR at the edges of gold nanostructures.