A Planar Scanning Probe Microscope

TL;DR

This paper introduces a simplified, tipless scanning probe microscopy technique using planar sensors and optical feedback, enabling high-precision imaging of electric and magnetic fields with improved sensor quality.

Contribution

It presents a novel tipless approach for scanning planar sensors, overcoming fabrication challenges and enhancing sensitivity and versatility in near-field imaging.

Findings

Successful near-field optical imaging of plasmonic modes in silver nanowires.

Achieved sub-mrad tilt and sub-nm distance measurement precision.

Demonstrated improved sensor quality and broader sensor applicability.

Abstract

Scanning probe microscopy (SPM) is traditionally based on very sharp tips, where the small size of the apex is critical for resolution. This paradigm is about to shift, since a novel generation of planar probes (color centers in diamond, superconducting sensors and single electron transistors) promises to image small electric and magnetic fields with hitherto inaccessible sensitivity. To date, much effort has been put into fabricating these planar sensors on tip-like structures. This compromises performance and poses a considerable engineering challenge, which is mastered by only a few laboratories. Here we present a radically simplified, tipless, approach - a technique for scanning an extended planar sensor parallel to a planar sample at a distance of few tens of nanometers. It is based on a combination of far-field optical techniques to measure both tilt and distance between probe and sample with sub-mrad and sub-nm precision, respectively. Employing these measurements as a feedback signal, we demonstrate near-field optical imaging of plasmonic modes in silver nanowires by a single NV center. Our scheme simultaneously improves the sensor quality and enlarges the range of available sensors beyond the limitations of existing tip-based schemes.