White light generation and anisotropic damage in gold films near percolation threshold

Abstract

Strongly enhanced and confined electromagnetic fields generated in metal nanostructures upon illumination are exploited in many emerging technologies by either fabricating sophisticated nanostructures or synthesizing colloid nanoparticles. Here we study effects driven by field enhancement in vanishingly small gaps between gold islands in thin films near the electrically determined percolation threshold. Optical explorations using two-photon luminescence (TPL) and near-field microscopies reveals super-cubic TPL power dependencies with white-light spectra, establishing unequivocally that the strongest TPL signals are generated with close to the percolation threshold films, and occurrence of extremely confined (~ 30 nm)and strongly enhanced (~ 100 times) fields at the illumination wavelength. For linearly polarized and sufficiently powerful light, we observe pronounced optical damage with TPL images being sensitive to both wavelength and polarization of illuminating light. We relate these effects to thermally induced morphological changes observed with scanning electron microscopy images. Fascinating physics involved in light interaction with near-percolation metal films along with their straightforward and scalable one-step fabrication procedure promises a wide range of fascinating developments and technological applications within diverse areas of modern nanotechnology, from bio-molecule optical sensing to ultra-dense optical data storage.

arXiv comment42 pages in total of the main (27 pages) and supplementary (15 pages) material with 4 main and 10 supplementary figures

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Cited by in corpus (8)

• Laser writing of bright colours on near-percolation plasmonic reflector arrays
• Giant enhancement of silicon plasmonic SWIR photodetection using nanoscale self-organised metallic films
• Holographic Resonant Laser Printing of metasurfaces using plasmonic template
• Wide-range Angle-sensitive Plasmonic Color Printing on Lossy-Resonator Substrates
• Optical reconfiguration and polarization control in semi-continuous gold films close to the percolation threshold
• Copper-based disordered plasmonic system with dense nanoisland morphology
• Thesis: Experimental exploration of gold semi-continuous films in the near- and far-field
• On-chip spectropolarimetry by fingerprinting with random surface arrays of nanoparticles