Noncontact tuning fork position sensing for hollow-pyramid near-field cantilevered probes

We demonstrate that tuning fork sensing provides a stable, noncontact mode of operation when applied to near-field optical microscopy employing cantilevered probes. Detrimental damping effects that have so far limited the practical use of these otherwise very advantageous probes are totally overcome. We validate our tuning fork setup featuring hollow-pyramid probes by an optical nanolithography application.