VITI L.

A novel scattering-type near-field optical microscopy (s-SNOM) system based on a terahertz (THz) quantum cascade laser operating in self-detection mode is employed to probe a resonant phonon-polariton mode of a thin topological insulator flake (Bi2Te2.2Se0.8). Background-free near-field imaging with nanoscale spatial resolution is demonstrated.

We report on the study of phonon polaritons modes in thin crystalline flakes of Bi2Se3 and Bi2(Te1-x Sex)3 as a function of the flake thickness, by means of two near-field THz techniques: phase resolved self-detection and THz time domain spectroscopy (TDS-SNOM). Background-free near-field imaging with nanoscale spatial resolution is demonstrated.

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...

Near-field imaging with terahertz (THz) waves is emerging as a powerful technique for fundamental research in photonics and across physical and life sciences. Spatial resolution beyond the diffraction limit can be achieved by collecting THz waves from an object through a small aperture placed in the near-field. However, light transmission...

Near-field imaging techniques at terahertz (THz) frequencies are severely restricted by diffraction. To date, different detection schemes have been developed, based either on sub-wavelength metallic apertures or on sharp metallic tips. However high-resolution THz imaging, so far, has been relying predominantly on detection techniques that...

At terahertz (THz) frequencies, scattering-type scanning near-field optical microscopy (s-SNOM) based on continuous wave sources mostly relies on cryogenic and bulky detectors, which represents a major constraint for its practical application. Here, we devise a THz s-SNOM system that provides both amplitude and phase contrast and achieves...