Lasing Emission from Plasmonic Nanodome Arrays

Plasmonic nano-dome arrays (PNDA) have been previously studied as chemical and biological sensors. The present study reports large-area plasmonic lasing from the PNDA structures with liquid-phase gain materials to provide optical gain. The PDNA structure consists of a 2D array of nanoposts, fabricated inexpensively using a nanoreplica molding process, with silicon dioxide and gold thin-film coatings to produce the dome-shaped surface profile. Covered with a dye-doped solution, the PDNA structures can generate lasing emission when they are optically pumped above the lasing threshold. The lasing emission is enabled by energy coupling from the photoexcited dye molecules to the hybridized plasmon mode supported by the PDNA oscillator. Two PDNA lasers with array periods of 400 and 450 nm are fabricated and characterized. Plasmonic resonant modes of the PDNA lasers are numerically studied to illustrate the underlying lasing mechanism. The emission characteristics, including lasing wavelength, linewidth, threshold, beam divergence, and radiation angle, are presented in the paper. The PNDA laser represents a new path for plasmonic lasing in the near-infrared region with potential applications that include integrated photonic circuits, optical communications, and high-performance biosensors.