Phase-resolved terahertz self-detection near-field microscopy

Giordano, Maria C.; Mastel, Stefan; Liewald, Clemens; Columbo, Lorenzo L.; Brambilla, Massimo; Viti, Leonardo; Politano, Antonio; Zhang, Kai; Li, Lianhe; Davies, A. Giles; Linfield, Edmund H.; Hillenbrand, Rainer; Keilmann, Fritz; Scamarcio, Gaetano and Vitiello, Miriam S. (2018): Phase-resolved terahertz self-detection near-field microscopy. In: Optics Express, Vol. 26, No. 14: pp. 18423-18435

Abstract

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 nanoscale (60-70nm) in-plane spatial resolution. It features a quantum cascade laser that simultaneously emits THz frequency light and senses the backscattered optical field through a voltage modulation induced inherently through the self-mixing technique. We demonstrate its performance by probing a phonon-polariton-resonant CsBr crystal and doped black phosphorus flakes.

• Item Type: Journal article
• Faculties: Physics
• Research Centers: Center for NanoScience (CENS)
• Subjects: 500 Science > 500 Science; 500 Science > 530 Physics
• ISSN: 1094-4087
• Language: English