Compact and high numerical aperture near-field microscopy based on piezo-probes

Background

The study of low energy excitations in quantum materials often relies on scattering-type scanning near-field optical microscopy at cryogenic temperatures (cryo-SNOM). Constructing such an apparatus is a daunting task, requiring the simultaneous accommodation of numerous fine-tuned components within a confined space. Furthermore, maintaining cryogenic temperatures is complicated by enhanced radiative heating from light sources, hindering the achievement of very low operating temperatures.

Technology

Researchers at Stony Brook University developed a piezo-based cryo-SNOM system employing metal-coated Akiyama probes for tip actuation and detection. Unlike cantilever-based AFM probes that use laser-based detection, this method relies on electrical means or a combination of mechanical excitation and electrical detection for the tip's oscillation. This design enables a compact system with high spatial resolution and near-field contrast, reducing the need for extensive high vacuum components and addressing challenges related to component accommodation and thermal management in cryogenic environments.