Angstrom-scale plasmonic gap boosts nonlinear light output by 2,000% per volt, a 2 orders of magnitude improvement

https://phys.org/news/2026-02-angstrom-scale-plasmonic-gap-boosts.html

"7 Å gap created by scanning tunneling microscope between metallic tip/ substrate... 1 V across gap generates 10^9 V/m field altering gap molecules' electronic states... 2nd-harmonic generation intensity changed quadratically with voltage, for precise electrical control... works across broad spectral range... ultra-compact electro-photonic devices where electrical/ optical signals interconverted at atomic scale... modulation depth ~2000% at ±1 V, also for sum-frequency generation, mid-IR to visible conversion"