with the particle number concentration Cp and the fiber length L [11].
The non-diffusion limited sampling method has an up to 100% collection efficiency of the particles flowing in the projection of the string resonator, which means that only very small volumes of dilute sample solutions are necessary to coat the resonator.
Eqs. (1), (2) and (3) demonstrate the importance of geometrical aspects when materials are deposited onto mechanical string resonators by non-diffusion limited sampling. The geometry of the resonators is equally important for their sensitivity, when measuring photothermal frequency detunings. The relative resonance frequency change of a mechanical string resonator with cross sectional area A and length L, which is exposed to a certain laser power P in its center, can be written as [13]
equation(4)