Near-field quantum nanoscopy in the far-infrared enabled by quantum cascade lasers: opinion

In this opinion article, I summarize some of the recent developments in the field of near-field nanoscopy of quantum materials in the far-infrared, highlighting the key role of the quantum cascade laser as a tool for building up unique near-field microscopes for mapping material and devices at the nanoscale, in a phase-sensitive, detectorless configuration, and I provide opinion on some of potential challenges and opportunities in the field.