January 8th 2026

Paper Alert!

We show that subwavelength cavities patterned at a metal–dielectric interface can efficiently launch and shape in-plane phonon polaritons in hexagonal boron nitride, acting as planar polaritonic lenses that control wavefront geometry. By tailoring cavity shapes, we achieve arbitrary focusing - including deep-subwavelength confinement down to λ/70—providing a fabrication-compatible route to mid-infrared polaritonic lenses, wavefront shapers, and metasurfaces without relying on anisotropic materials.

Thank you all, who contributed to the project. Specials thanks to Dr. Bogdan Borodin and Dr. Sergey Lepeshov for leading experimental and theory parts!

Cheers!

Read the full story here (open access): https://www.nature.com/articles/s42005-025-02451-0