Fundamental limits to local density of states in absorptive system

Abstract

Fundamental limits to optical responses such as absorption, scattering and local density of states (LDOS) are proposed given intrinsic material losses by Owen, etc. The absorption and scattering limits are validated in Owen's work while the LDOS of common structures fall short of the limits. To validate those theoretical limits in LDOS, comprehensive studies are conducted in the metallic cavity structures, as typical resonant cavities will produce high LDOS. A novel shape optimization method based on the adjoint method is presented in this work, several numerical methods (BEM, CGAL, etc.) and optimization methods are implemented to enable more efficient evaluation and reduce the computation costs.