Method for tuning light extinction by thermal expansion of coated nanoparticles

摘要

We propose a novel method for all-optical modulation. Our method is based on tuning the dimensions of nanoparticles by manipulating thermal energy. The excitation characteristics of coated nanoparticles change following minor variations in their dimensions. This is because incident radiation will encounter particles with an altered extinction cross section. We considered nanoparticles comprising gold cores with silica coating. We found distinct nanoparticle dimensions that exhibit steep changes in their optical extinction cross section under thermal expansion. Based on these dimensions we calculated the optical contrast. The results showed that optical contrast reaches 1.86 dB for radii of 900 nm.