Measurement of decay lengths of evanescent waves: the lock-in non linear filtering
New Journal of Physics
We study the influence of the lock-in amplifier and probe vibration on the measurement of decay lengths of evanescent waves after reconstruction of the Scanning Near-field Optical Microscopy signal. Thanks to the reconstruction which gives a tomography-like 3D map of the detected signal, the vertical decay lengths can be measured directly, from only one lateral scan. A nonlinear fit is applied to recover the exponential decays in simulated signals and experimental data.