Propagation lengths of surface plasmon polaritons on metal films with arrays of subwavelength holes by infrared imaging spectroscopy

Abstract

Metal films with arrays of subwavelength holes (mesh) exhibit extraordinary transmission resonances to which many attribute a role for surface plasmon polaritons (SPPs); others debated this point. Experimental measurements of propagation lengths are presented under conditions that pertain to the use of SPPs for surface spectroscopy. The lateral extent of electromagnetic propagation along the mesh surface is measured by recording absorption spectra of a line of latex microspheres as a function of distance away from the line along the mesh. Measurements reveal an exponential functional form for decay of absorption signal laterally from the absorption source. Results at 697 cm−1, which are closest to the strongest transmission resonance of the mesh, reveal a 1/e propagation distance along the surface of 17.8±2.9 μm. This is 40% larger than the lattice spacing implicating the holes as the SPP damping mechanism, however, this is significantly shorter than smooth metal expectations.

Quantifying Remote Heating from Propagating Surface Plasmon Polaritons

“…Remote plasmon excitation via grating was used to increase the laser light focusing and improve spatial separation in the tip-enhanced Raman spectroscopy of surface molecules . Remote plasmon excitation has also been induced to perform SERS of molecules adsorbed at distal positions along metallic nanowires. , Remote heating and coupling of optical energy into metallic point contacts has been achieved via SPP excitation by illuminating devices with specially designed gratings or wave guides. , The SPP propagation length can exceed tens of microns − and is usually measured by designing a second antenna-type structure at a specified distance to convert SPP to a free photon for optical detection. ,− SPP excitation can be also detected via electronic transport measurements due to its effects on device conductance. − This electrical SPP detection technique is beneficial in eliminating the additional burden of optical detection but does not provide a quantitative assessment of the steady state heating contribution from the SPP dissipation.…”

Modifying infrared scattering effects of single yeast cells with plasmonic metal mesh

“…The mesh has a 12.6 m hole-center to hole-center spacing ͑lattice parameter͒, a 5.0-5.5 m hole width, and a thickness of ϳ2.0 m. Light incident on the metal is not directly transmitted, but can still get through the hole by plasmonic mechanisms. 19,[46][47][48] The yeast cells are about the same size as the Ni metal mesh holes, and the evaporation process causes the cells to be drawn into the holes of the mesh ͑probably by capillary forces͒. The spacing of the mesh holes primarily defines the accessible IR range, and the specific size of the holes must match the cells to be studied, so cells of other sizes would likely require noncommercial sources of mesh.…”

Dust Library of Plasmonically Enhanced Infrared Spectra of Individual Respirable Particles

“…The mesh has interesting optical properties including the reduction of scattering effects and the production of undistorted vibrational lineshapes of a trapped individual particle. 31,32 The Coe group has recorded IR spectra of individual subwavelength particles including live yeast cells, 11 latex microspheres, 32,33 and calibrant materials 10 (quartz, gypsum, carbonates, different types of clay, humic acid/salt). This work applies a common analysis 10 to three dust samples, including dust from lab air, 10 a home air filter, 15 and the September 11, 2001 World Trade Center event by using plasmonic Ni mesh and an imaging FTIR microscope.…”