Theory of Multiple Scattering Enhanced Single Particle Plasmonic Sensing

Abstract

Methods to increase the light scattered from small particles can help improve the sensitivity of many sensing techniques. Here, we investigate the role multiple scattering plays in perturbing the scattered signal when a particle is added to a random scattering environment. Three enhancement factors, parametrising the effect of different classes of multiple scattering trajectories on the field perturbation, are introduced and their mean amplitudes explored numerically in the context of surface plasmon polariton scattering. We demonstrate that there exists an optimum scatterer density at which the sensitivity enhancement is maximised, with factors on the order of 10 2 achievable. Dependence of the enhancement factors on scatterer properties are also studied.

Invariance property of the Fisher information in scattering media

“…In these contexts, multiple scattering effects are usually seen as a major drawback, limiting the achievable precision in the estimation of observable parameters characterizing the particles. Nevertheless, it is also known that such multiple scattering effects can sometimes be beneficial to optical imaging [4][5][6][7] as well as to single-particle localization and sensing [8][9][10][11], especially if prior knowledge on the scattering environment is available to the observer [12,13]. These insights naturally raise the question of how the presence of such a complex environment surrounding a subwavelength particle influences the information carried by the field scattered by the particle.…”