Ultrahigh-Resolution, Label-Free Hyperlens Imaging in the Mid-IR

Area of Science:

• Nanophotonics
• Metamaterials
• Solid-state physics

Background:

• Hyperbolic phonon polaritons in hexagonal boron nitride (hBN) offer potential for super-resolution imaging via hyperlensing due to long scattering lifetimes.
• Current hyperlens imaging faces limitations in resolving closely spaced objects and correlating complex fields with sample structures.

Purpose of the Study:

• To enhance spatial resolution in hyperlens imaging using monoisotopic hBN.
• To develop an image reconstruction algorithm for accurate visualization of embedded objects.
• To provide insights for optimizing hyperlens performance for far-field imaging.

Main Methods:

• Utilizing monoisotopic h¹¹BN for hyperbolic phonon polariton generation.
• Experimental demonstration of hyperlens imaging at a 6.76 μm free-space wavelength.
• Development and application of a novel image reconstruction algorithm.

Main Results:

• Achieved significant improvements in spatial resolution, resolving structures as small as 44 nm.
• Demonstrated resolution of spacings below 25 nm.
• Generated structurally accurate images of embedded objects from complex hyperlens fields.

Conclusions:

• Monoisotopic hBN significantly advances hyperlens imaging resolution and capability.
• The developed image reconstruction algorithm enables accurate visualization of nanoscale structures.
• This work paves the way for label-free, high-resolution, spectrally selective far-field imaging modalities.