A super-oscillatory lens optical microscope for subwavelength imaging

Abstract

The past decade has seen an intensive effort to achieve optical imaging resolution beyond the diffraction limit. Apart from the Pendry-Veselago negative index superlens, implementation of which in optics faces challenges of losses and as yet unattainable fabrication finesse, other super-resolution approaches necessitate the lens either to be in the near proximity of the object or manufactured on it, or work only for a narrow class of samples, such as intensely luminescent or sparse objects. Here we report a new super-resolution microscope for optical imaging that beats the diffraction limit of conventional instruments and the recently demonstrated near-field optical superlens and hyperlens. This non-invasive subwavelength imaging paradigm uses a binary amplitude mask for direct focusing of laser light into a subwavelength spot in the post-evanescent field by precisely tailoring the interference of a large number of beams diffracted from a nanostructured mask. The new technology, which--in principle--has no physical limits on resolution, could be universally used for imaging at any wavelength and does not depend on the luminescence of the object, which can be tens of micrometres away from the mask. It has been implemented as a straightforward modification of a conventional microscope showing resolution better than λ/6.

[INVITED] Epsilon-near-zero metalenses operating in the visible

“…An improved resolution (e.g. super resolution) of the metalenses may be, however, obtained using different techniques 35 but it is beyond of the scope of this manuscript.…”

Upholding the diffraction limit in the focusing of light and sound

“…Recently, efforts in this direction have been intensified [14,36,37,38], taking advantage of the progress achieved in nanofabrication. A reduction of the FWHM of the central spot below /2 at the expense of large sidebands has also been observed in Veselago-type acoustic focusing by phononic-crystal structures without apodization [15,33].…”

“…In 2006, Berry and Popescu [40] proposed to use this effect for superresolution focusing, apparently without knowing of the prior work by Toraldo di Francia and others. Since then, the term 'superoscillations' is commonly used to describe this phenomenon in the propagation of classical waves such as light and sound [14,33,36,37].…”

Creation of Super-Resolution Non-Diffraction Beam by Modulating Circularly Polarized Lightwith Ternary Optical Element

“…However, it is difficult to realize the spot below diffraction limit due to the optical diffraction limit effect. In order to break through the diffraction limit, lots of ways to obtain super-resolution non-diffraction beam were presented and discussed such as hyperlens and super-oscillatory lens [9][10][11], utilizing superlens to turn evanescent waves into propagating waves and obtain subwavelength imaging [12,13], handling of the evanescent waves with near field diffraction structures [2,14], and super-resolution apodization through pupil masks [14][15][16][17][18]. In these methods, the superresolution pupil filters (or phase plates) with amplitude and phase modulations are always hot subjects.…”