Phase-sensitive terahertz imaging using room-temperature near-field nanodetectors

TL;DR

This paper introduces a room-temperature nanodetector integrated into a near-field probe for phase-sensitive terahertz imaging, enabling high-resolution, coherent imaging without cryogenic cooling or ultrafast lasers.

Contribution

The study presents a novel room-temperature nanodetector embedded in a near-field probe for phase-sensitive THz imaging, advancing high-resolution imaging capabilities.

Findings

Achieved sub-wavelength spatial resolution in THz imaging.

Demonstrated phase-sensitive imaging of confined THz fields.

Enabled high-sensitivity coherent THz imaging at room temperature.

Abstract

Imaging applications in the terahertz (THz) frequency range are severely restricted by diffraction. Near-field scanning probe microscopy is commonly employed to enable mapping of the THz electromagnetic fields with sub-wavelength spatial resolution, allowing intriguing scientific phenomena to be explored such as charge carrier dynamics in nanostructures and THz plasmon-polaritons in novel 2D materials and devices. High-resolution THz imaging, so far, has been relying predominantly on THz detection techniques that require either an ultrafast laser or a cryogenically-cooled THz detector. Here, we demonstrate coherent near-field imaging in the THz frequency range using a room-temperature nanodetector embedded in the aperture of a near-field probe, and an interferometric optical setup driven by a THz quantum cascade laser (QCL). By performing phase-sensitive imaging of strongly confined THz fields created by plasmonic focusing we demonstrate the potential of our novel architecture for high-sensitivity coherent THz imaging with sub-wavelength spatial resolution.