About size distribution of particles adsorbed to a spherical whispering-gallery-mode resonator in sensing experiments

Whispering-gallery-mode (WGM) resonators are actively used to sense and size nanoparticles. In a typical experimental setup a WGM resonator is placed in a solution to which particles to be sensed are also added. The size of the particle is inferred from the changes in the spectrum of WGM resonances caused by adsorption of the particle to the resonator's surface. The inference often depends on the assumptions about statistical distribution of the particle sizes. We show in this work that the distribution of sizes of the particles actually detected by the resonator differs from the distribution of sizes in the total population of the particles. This phenomenon, which is currently not being taken into account when interpreting experimental data, might distort sizing information extracted from such experiments.