Optical lever detection in higher eigenmode dynamic atomic force microscopy

摘要: The optical lever detection scheme is widely used in atomic force microscopy for the of cantilever deflection. Laser spot size as well adjustment laser along determine zeros transfer function signal path from tip-sample forces to readout. This can cause (almost) pole-zero cancellations which lead a significantly reduced sensitivity higher mode vibrations cantilever. Physically, light integrates over slope However, sign flexural modes varies Thus, integration decreased eigenmode vibrations. Illuminating only area between free end and next zero crossing modal shape provides good compromise high low frequency sensitivity.