Terahertz non-label subwavelength imaging with composite photonics-plasmonics structured illumination

TL;DR

This paper introduces a terahertz non-fluorescent subwavelength imaging technique using structured illumination with plasmonics, achieving resolution enhancement up to 0.12 lambda and potential for applications in weak scattering sample detection.

Contribution

It proposes a novel terahertz structured illumination method employing spoof surface plasmons for non-fluorescent subwavelength imaging, surpassing traditional resolution limits.

Findings

Resolution improved to 0.12 lambda

High order spatial frequencies encoded into low order ones

Resolution tunable by adjusting SSPs frequency

Abstract

Inspired by the capability of structured illumination microscopy in subwavelength imaging, many researchers devoted themselves to investigating this methodology. However, due to the free propagating feature of the traditional structured illumination fields, the resolution can be only improved up to double times compared with the diffractied limited microscopy. Besides, most of the previous studies, relying on incoherent illumination sources, are restricted to fluorescent samples. In this work, a subwavelength nonfluorescent imaging method is proposed based on the terahertz traveling wave and plasmonics illumination. Excited along with a metal grating, the spoof surface plasmons are employed as the plasmonics illumination. When the scattering waves with the SSPs illumination are captured, the high order spatial frequency components of the sample are already encoded into the obtainable low order ones. Then, an algorithm is summarized to shift the modulated SF components to their actual positions in the Fourier domain. In this manner, high order SF components carrying the fine information are introduced to reconstruct the desired imaging, leading to an improvement of the resolution up to 0.12 lambda. Encouragingly, the resolution can be further enhanced by tuning the working frequency of the SSPs. This method holds promise for some important applications in terahertz nonfluorescent microscopy and sample detection with weak scattering.