Silicon nanowire/polymer membrane for infrared visualization via third-harmonic generation

Nonlinear harmonic generation in nanostructures is one of the key topics in nanophotonics, as it allows infrared-to-visible light conversion at the nanoscale.his work reports on the efficient third-harmonic generation in a free-standing Si nanowire array encapsulated into a polymer membrane. High nonlinearity of Si material X 31112.45 ≈ 10 –19m2 /V 2 and light coupling with optical resonances in the nanowires yield a strong third-harmonic signal and efficient infrared (1200 — 2000nm) to visible (400 — 666nm) upconversion. The fabricated membranes demonstrate high flexibility and semitransparency, which makes them convenient to use as visualizers.