Femtosecond Laser-Excited Two-Photon Fluorescence Microscopy of Surface Plasmon Polariton

Abstract

We demonstrate microscopic imaging of surface plasmon polaritons (SPPs) on silver films excited by 11 fs near-infrared laser pulses. A fluorescence layer placed on the silver film converts surface electromagnetic fields to propagating lights in visible wavelengths via two-photon excitation process. The wavelength of SPP determined from fluorescence micrographs agrees well with the calculated value of SPP at the silver-fluorescent film interface.

Spatiotemporal Characterization of SPP Pulse Propagation in Two-Dimensional Plasmonic Focusing Devices

“…The approach presented here is not only restricted to ITR-PEEM experiments but can also be applied to other experimental techniques where plasmon propagation is probed by the interference with a reference laser field. 45 Prospects of this approach include the analysis of time-resolved data in terms of SPP phase modulation in highly dispersive plasmonic systems that should give rise to a wave packet broadening during propagating. The method demonstrated here for time-resolved recording of SPP propagation in complex two-dimensional plasmon-optical assemblies further provides the possibility to analyze the temporal evolution of SPP pulses prepared with defined amplitude and/or phasemodulation by laser pulse-shaping techniques.…”

Observation of ultrabroadband striped space-time surface plasmon polaritons

“…Along the transverse direction, the fluorescence image shows a periodicity equal to a half of that of a strived ST-SPP, reflecting two antinodes incorporated in one cycle of the transverse profile. The axial beating is the result of interference between the free-space ST wave packet and the surface-bound striped ST-SPP [55,56]. These observations provide evidence for the feasibility of synthesizing arbitrary ST-SPPs that incorporate a multiplicity of spatial frequencies [50].…”

“…Typically, the out-ofplane component dominates the field intensity. The two-photon-fluorescence emission is collected with an objective lens (M Plan Apo SL20X, Mitutoyo) equipped with a band-pass filter transmitting light in the range 475 − 495 nm (Semrock, FT-02-485/20-25), followed by a CCD camera (Rolera EM-C2, QImaging) [55,56]. The intensity I(x, z) detected by the CCD camera is a time integral of the fourth power of the total electric field.…”

Spectral and temporal modulations of femtosecond SPP wave packets induced by resonant transmission/reflection interactions with metal-insulator-metal nanocavities

“…The MIM nano-cavities were formed by putting a Au nano-block with a thickness h of 100 nm and a length L ranging from 10 to 500 nm on the Al2O3 film. In addition, the whole surface was covered with a poly(methyl methacrylate) (PMMA) layer with a thickness w of 60 nm to simulate experimental microscopic imaging conditions [45]. The only effect of this additional PMMA layer was a slight increase in the effective refractive index of the SPPs.…”