Spatial Distribution of the Nonlinear Photoluminescence in Au Nanowires

Abstract

When gold nanowires are excited with a tightly focused femtosecond laser a distributed nonlinear photoluminescence (N-PL) develops throughout the entire structure. A complete spaced-resolved analysis of the spectral signature of the nanowire nonlinear response is carried out to understand the origin of the distributed nonlinear response. We discuss various mechanisms to explain the experimental data and unambiguously demonstrate that the spatial and spectral extension of the N-PL in the nanowire are mainly dictated by the propagation of a surface plasmon excited at the pump wavelength. We also present experimental signature of near-field excitation of a broadband continuum of surface plasmons excited locally throughout the N-PL emission spectrum.

Electrostatic Control over Optically Pumped Hot Electrons in Optical Gap Antennas

“…Another phenomenon that could contribute to a change in the N-PL rate is a modification of the morphology of the optical gap antenna imposed either by the laser or a by a field-induced reorganization of the metal interface. , Since the modulation amplitude does not significantly change in the time traces presented above, we conclude that the structure under illumination does not undergo an irreversible reshaping and the intensity of the laser remains below the damage threshold . Like second-harmonic generation arising in small Au structures, N-PL is believed to be a surface effect. , Hence, a reversible electric field-induced reorganization of the metal outer boundaries would necessarily affect the strength of both the N-PL and the SHG signals. Reordering of the Au outmost atomic layers was found to occur for local field magnitudes in excess of 25 × 10 9 V·m –1 , a value two orders of magnitude higher than typical fields applied in our experiment.…”

“…27 Like second-harmonic generation arising in small Au structures, N-PL is believed to be a surface effect. 5,37 Hence, a reversible electric field-induced reorganization of the metal outer boundaries would necessarily affect the strength of both the N-PL and the SHG signals. Reordering of the Au outmost atomic layers was found to occur for local field magnitudes in excess of 25 × 10 9 V•m −1 , 35 a value two orders of magnitude higher than typical fields applied in our experiment.…”

Theory of “Hot” Photoluminescence from Drude Metals

“…We confirm some of the assumptions underlying the “hot” PL analyses made in ref and but also make these more exact and complete (with respect to the photonic aspect of the theory). Beyond these fundamental aspects of the problem, our results provide the underlying theory for the metal PL-based thermometry techniques that emerged recently − and constitute a first step toward a more complete theory applicable also for interband emissions and transient PL. ,,,, …”

Interconnect-Free Multibit Arithmetic and Logic Unit in a Single Reconfigurable 3 μm2 Plasmonic Cavity

“…When a femtosecond pulsed laser is focused on a high SPLDOS spot, it efficiently drives the plasmon resonance and generates nonlinear photoluminescence (nPL) not only at the excitation spot but also in the most remote regions of a specific near-field pattern. ,, In this work, the nPL is used as an all-optical observable of the transfer function of the device . The threshold readout of the nPL signal intensity, recorded in arbitrary units on a 8-bit registry from a diffraction-limited region, represents the logical output of the device that is associated with the logical inputs encoded in the linear polarization directions of the excitation beams.…”