3-D Topology Optimization of Spatially Averaged Surface-Enhanced Raman Devices

Abstract

Numerous nanophotonics applications necessitate designs that enhance distributed incoherent emission. Representative applications include light-emitting diodes, thermal emitters, and Raman sensing. Previous efforts in full-scale topology optimization for Surface Enhanced Raman Sensing (SERS) have predominantly focused on single particle emissions or two-dimensional systems, which are impractical for actual fabrication. An objective function represented by ട|E|⁴dV effectively approximates Raman enhancement. This function tends to diverge near sharp tips and other singular geometries in three-dimensional spaces for relevent materials. This thesis delves into methodologies for regularizing the optimization process to preclude the formation of such problematic geometries. Additionally, it integrates lithography constraints to ensure that the optimized SERS substrates are viable for fabrication. To align with computational limits, various strategies are employed to make the system manageable. The techniques developed in this study facilitate the practical design of 3-D systems that enhance incoherent emission through topology optimization.