Polarization- and angle-independent, dual-band metasurface thermal emitter was developed. The metasurface emits radiation at 4.26 μm and 3.95 μm, conventionally used for CO2 sensing. The metasurface is based on a planar Au/Al2O3/Au structure, in which orthogonal rectangular Au patches are arrayed alternately, and generates nearly perfect blackbody radiation with an emittance as high as 0.97. The metasurface is integrated on a resistive heater mounted on a SiN membrane, so that the infrared waves are produced by applying a voltage. The metasurface emitter was incorporated into an actual CO2 sensing system and was demonstrated to reduce the electric power needed by about 30% compared with a conventional blackbody emitter by suppressing unnecessary radiation.

Lanthanoid series are unique in atomic elements. One reason is because they have 4f electronic states forbidding electric-dipole (ED) transitions in vacuum and another reason is because they are very useful in current-day optical technologies such as lasers and fiber-based telecommunications. Trivalent Er ions are well-known as a key atomic element supporting 1.5 μm band optical technologies and also as complex photoluminescence (PL) band deeply mixing ED and magnetic-dipole (MD) transitions. Here we show large and selective enhancement of ED and MD radiations up to 83- and 26-fold for a reference bulk state, respectively, in experiments employing plasmonic nanocavity arrays. We achieved the marked PL enhancement by use of an optimal design for electromagnetic (EM) local density of states (LDOS) and by Er-ion doping in deep subwavelength precision. We moreover clarify the quantitative contribution of ED and MD radiations to the PL band, and the magnetic Purcell effect in the PL-decay temporal measurement. This study experimentally demonstrates a new scheme of EM-LDOS engineering in plasmon-enhanced photonics, which will be a key technique to develop loss-compensated and active plasmonic devices.

We have experimentally shown significant suppression of metal-induced fluorescence (FL) quenching on plasmo-photonic metasurfaces by incorporating a self-assembled monolayer (SAM) of sub-nm thickness. The FL signals of rhodamine dye molecules have been several-ten-fold enhanced by introducing the SAM, in comparison with the previous configuration contacting molecules and metal surfaces.

Abstract. We fabricated large-area stacked complementary plasmonic crystals (SC PlCs) by employing ultraviolet nanoimprint lithography. The SC PlCs were made on silicon-on-insulator substrates consisting of three layers: the top layer contacting air was a perforated Au film, the bottom layer contacting the buried oxide layer included an Au disk array corresponding to the holes in the top layer, and the middle layer was a Si photonic crystal slab. The SC PlCs have prominent resonances in optical wavelengths. It is shown that the fabricated PlCs were precise in structure and uniform in their optical properties. We examined the photoluminescence (PL) enhancement of monolayer dye molecules on the SC PlC substrates in the visible range and found large PL enhancements of up to a 100-fold in comparison with dye molecules on nonprocessed Si wafers. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.