A planar scanning probe microscope for near-field microscopy

Abstract

Scanning probe microscopy (SPM) traditionally employs a sharp tip as a sensor. This geometry is a problem for many modern near-field probes, such as NV centers in diamond, which cannot easily be placed on a tip. Here we present a novel, tipless approach - a technique to scan a planar probe parallel to a planar sample at a distance of few tens of nanometers. The core of our scheme are optical far-field techniques to measure both distance and tilt between the probe and the sample with sub-nm and sub-mrad precision. These measurements are employed as a feedback signal for positioning. Using this scheme, we demonstrate scanning near-field optical microscopy (SNOM) of plasmonic modes in silver nanowires using shallow NV centers in a bulk diamond. We will equally present ongoing experiments to implement a scanning nanogap cavity. S. Ernst et al., ACS Photonics 6, 327 (2019)