Superlensing without a super lens: Physicists boost microscopes beyond limits

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"... Now physicists at the University of Sydney have shown a new pathway to achieve superlensing with minimal losses, breaking through the diffraction limit by a factor of nearly four times. The key to their success was to remove the super lens altogether. ..."

"... “To do this, we placed our light probe far away from the object and collected both high- and low-resolution information. By measuring further away, the probe doesn’t interfere with the high-resolution data, a feature of previous methods.” ... “We overcome this by performing the superlens operation as a post-processing step on a computer, after the measurement itself. This produces a ‘truthful’ image of the object through the selective amplification of evanescent, or vanishing, light waves. ..."

From the abstract:

"Imaging with resolutions much below the wavelength λ – now common in the visible spectrum – remains challenging at lower frequencies, where exponentially decaying evanescent waves are generally measured using a tip or antenna close to an object. Such approaches are often problematic because probes can perturb the near-field itself. Here we show that information encoded in evanescent waves can be probed further than previously thought, by reconstructing truthful images of the near-field through selective amplification of evanescent waves, akin to a virtual superlens that images the near field without perturbing it. We quantify trade-offs between noise and measurement distance, experimentally demonstrating reconstruction of complex images with subwavelength features down to a resolution of λ/7 and amplitude signal-to-noise ratios < 25dB between 0.18–1.5 THz. Our procedure can be implemented with any near-field probe, greatly relaxes experimental requirements for subwavelength imaging at sub-optical frequencies and opens the door to non-invasive near-field scanning."

Superlensing without a super lens: Physicists boost microscopes beyond limits (secondary news source)

Superlensing without a superlens: microscopes boosted beyond limits (primary news source) New technique could be used in medical imaging and advanced manufacturing

Subwavelength terahertz imaging via virtual superlensing in the radiating near field (open access)

Fig. 1: Concept schematic of virtual superlens.