Enhanced two-photon luminescence from nanoporous gold capped with microcontact-printed salts.

We report that a nanoporous Au film capped with a dielectric surface layer enables the effective absorption of near-infrared light and intense emission of two-photon luminescence. In this approach, nanoscale pores in Au are incorporated by chemical dissolution and microscale surface patterns are added on the nanoporous Au by microcontact print lithography. Electromagnetic simulation shows that the strong local electric fields are concentrated in the vicinity of nanopores in the Au film and are further increased by the surface dielectric patterns, which leads to a 40-fold increase in the intensity of the two-photon luminescence, as verified by photoemission measurement. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]