Light can be generated deep inside a solid material and detected far away from where the laser hit.
Measuring the hidden layers where two different materials meet usually requires blasting them with high-powered lasers that can damage the sample. This new method uses surface plasmons to carry energy along the material to a different spot before it converts into a detectable light signal. This process allows researchers to see what is happening at buried interfaces without needing a direct line of sight. It bypasses the physical barriers that normally block sensors from inspecting the inner workings of a device. This capability is a game-changer for inspecting the internal health of computer chips and batteries without taking them apart.
Plasmon Induced Delocalized Second-Harmonic Generation Towards Buried-Interface Spectroscopy
arXiv · 2605.00575
Second-harmonic generation microscopy is a powerful technique capable of probing local crystal symmetries and electric fields at interfaces. However, it often suffers from weak signal strength and is difficult to understand in multilayer systems where many materials can give competing signal contributions. In this work we present direct observation of delocalized, surface plasmon polariton-mediated second-harmonic generation on gold monocrystalline surfaces and structures. We generate second-har