A Local Superlens

Abstract

Superlenses enable near-field imaging beyond the optical diffraction limit. However, their widespread implementation in optical imaging technology so far has been limited by large-scale fabrication, fixed lens position, and specific object materials. Here we demonstrate that a dielectric lamella of subwavelength size in all three spatial dimensions behaves as a compact superlens that operates at infrared wavelengths and can be positioned to image any local microscopic area of interest on the sample. In particular, the lamella superlens may be placed in contact with any type of object and therefore enables examination of hard-to-scan samples, for example, with high topography or in liquids, without altering the specimen design. This lamella-based local superlens design is directly applicable to subwavelength light-based technology, such as integrated optics.

Polarization-dependent near-field phonon nanoscopy of oxides: SrTiO3, LiNbO3 , and PbZr0.2Ti0.8Wehmeier1, Lang2, Liu3 et al. 2019Phys. Rev. BSelf Cite235230View full textAdd to dashboardCite

“…53 For illumination of our SNOM-tip, we use the narrow-band free-electron laser FELBE at Helmholtz-Zentrum Dresden-Rossendorf, Germany. 19,[24][25][26][27]30,35,38,106,107 It is a tunable, linearly polarized laser source with a repetition rate of 13 MHz (quasi-continuous mode), which covers the infrared wavelength regime from 5 -250 µm, i.e. 40 -2000 cm −1 or 1.2 -60.0 THz.…”

“…For the near-field investigations we use a home-built s-SNOM 19,24,27,30,35,38,106,107 : We implement a self-homodyne detection scheme 74 in combination with higher-harmonic demodulation 28,74,108 to distinguish the desired near-field response from far-field contributions.…”

Review of near-field optics and superlenses for sub-diffraction-limited nano-imaging

“…The problem of depositing a large high-quality superlens can also be avoided by instead utilizing a "local superlens." 180 Here a small BaTiO 3 lamella with subwavelength dimensions was placed over an imaging area in free space. The resulting sub-diffraction-limited resolution underlines the localized nature of the excited phonon polariton modes, and also opens the possibility of depositing local superlenses on areas of interest on a sample instead of a larger lens that is likely to contain material defects or unwanted topographical features.…”

Enhancing the Resolution of Imaging Systems by Spatial Spectrum Manipulation

“…aperture are given by Bethe [72] and Bouwkamp. [73] Similar calculations for the specific case of a SNOM aperture probe were later carried out by Drezet et al [74,75] However, the brief analysis presented here is sufficient to understand the localization of the near-field radiation relevant to the general aperture SNOM concept.…”

“…There is no theoretical restriction to scaling our ACI method to other frequencies. The images could then be directly read out with a subwavelength near-field probe [2,6,66,67,68,69,70,71,72,73,74] or detector [75,76,77,78,79,80,81,82,83,84] small enough to resolve the important features.…”